B2 Verb Tenses 12 min read むずかしい

未来完了進行形：継続の時制

It highlights an action's duration leading up to a specific future moment.
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Grammar Rule in 30 Seconds

Use this tense to emphasize how long an action will have been happening by a specific point in the future.

  • Use 'will have been' + '-ing' for all subjects. Example: 'I will have been waiting.'
  • Always include a time reference like 'by next week' or 'for three hours'.
  • Avoid using stative verbs like 'know' or 'believe' in this continuous form.
Subject + ⏳ will have been + 🏃‍♂️ Verb-ing

Overview

### Overview
未来完了進行形（Future Perfect Continuous Tense）は、B2レベルの文法項目で、未来のある時点までに、ある動作がどれくらいの期間継続しているかを表現するために使われます。まるで未来の時点に立って、そこから振り返り、その時点までにその動作がどれくらいの長さ続いていたかを測るようなイメージです。この時制の主な機能は、動作の完了ではなく、その継続性と期間を強調することにあります。
この時制が存在する理由は、英語の文法が、過去・現在・未来のいずれかの時点から始まる継続的な動作が、未来のある時点まで続いている、という状況を正確に表現する必要があるからです。他の未来時制は「何が起こるか」を述べることはできますが、未来完了進行形は「どれくらいの期間、それが続いていたか」を説明するための文法的な道具なのです。これは、未来における持続性、コミットメント、そして長期間の活動の結果として生じる因果関係について議論する際に役立ちます。
### How This Grammar Works
未来完了進行形を理解するためには、その4つの構成要素を分解する必要があります。それぞれの要素が意味の層を加え、正確な時間的表現を組み合わせています。この構造は、過去または進行中の動作と未来のチェックポイントを結びつけます。
  1. 1will (未来の基準点)：この助動詞は、未来の参照点を確立します。文脈全体が未来に設定されていることを示します。例えば、「by December（12月までに）」「when you arrive（あなたが到着する時までに）」のような未来のある時点を、旗を立てるようにイメージしてください。
  1. 1have (完了のアスペクト)：この助動詞は「完了」のアスペクトを導入します。完了のアスペクトは、常に2つの異なる時点を結びつけます。この場合、未来の基準点の前の期間をその基準点に結びつけます。未来の時点から過去を振り返るような視点を作り出します。
  1. 1been (進行形の基盤)：be動詞の過去分詞であるbeenは、haveと共に完了のアスペクトを形成しますが、その存在があるからこそ、後に続く現在分詞（-ing形）を伴うことができ、進行中の、期間を伴う状態を示します。
  1. 1現在分詞 -ing (動作の期間)：これは主要動詞であり、その-ing形は、その動作が単一の完了した出来事ではなく、プロセスとしての継続的なものであることを意味します。これがこの時制の核心です。ある期間にわたって何かを行うプロセスに焦点を当てます。
概念的には、あなたは未来の時点であるwillに立って、have beenを使って、-ingで表される継続的な道のりを振り返っているのです。例えば、「By next year, I'll have been working here for a decade.（来年で、私はここで10年間働き続けていることになります。）」という文では、あなたは「来年」という未来の時点にいて、「働く」という10年間の道のりを振り返っています。
### Formation Pattern
未来完了進行形の文法的な公式は厳格で統一されています。このパターンを習得することが、肯定文、否定文、疑問文でこの時制を正しく使用するための鍵となります。
肯定文:
主語 + will + have + been + 現在分詞 (-ing形)
  • Next month, you will have been living here for five years.（来月で、あなたはここに5年間住み続けていることになります。）
短縮形（話し言葉やインフォーマルな書き言葉でよく使われます）:
  • I will → I'll (I'll have been...)
  • You will → You'll (You'll have been...)
  • He/She/It/We/They will → He'll/She'll/It'll/We'll/They'll
  • 例：By the time she calls, we'll have been cooking for hours.（彼女が電話してくるまでには、私たちは何時間も料理し続けていることになります。）
否定文:
主語 + will not (won't) + have + been + 現在分詞 (-ing形)
  • Don't worry, we won't have been waiting long by the time you get here.（心配しないで、君がここに着く頃には、私たちはそんなに長く待っていることにはならないでしょう。）
  • By 2025, he will not have been managing the team for a full year yet.（2025年までに、彼はまだ1年間チームを管理し続けていることにはなりません。）
疑問文:
Will + 主語 + have + been + 現在分詞 (-ing形)?
  • Will you have been working for twelve hours straight by the end of your shift?（シフトが終わるまでに、あなたは丸12時間働き続けていることになりますか？）
  • How long will they have been traveling by the time they reach Tokyo?（東京に着くまでに、彼らはどれくらいの期間旅行し続けていることになりますか？）
### When To Use It
この時制は、期間が最も重要な情報である特定の状況のために予約されています。これを正しく使用することは、英語の時間概念に対する洗練されたコマンドを示します。
  • 未来のある時点までの動作の期間を強調するため: これが主な機能です。焦点は、動作がどれくらいの期間進行していたか、です。動作は未来の瞬間まで続くか、その直前に終わります。
  • By the time the concert ends, the band will have been playing for three hours.（コンサートが終わるまでに、バンドは3時間演奏し続けていることになります。）（3時間の期間に焦点が当たっています。）
  • In September, we will have been renovating our house for a full year.（9月で、私たちは家を改装し続けて丸1年になります。）（長い改装期間を強調しています。）
  • 未来の状態や出来事の原因を説明するため: この時制は、未来における因果関係を示すために使用されます。長期間継続した動作が、未来の結果の原因となります。
  • When you see him, his hands will be dirty because he will have been gardening all afternoon.（彼に会うとき、彼は午後の間ずっと庭仕事をし続けていたので、手が汚れているでしょう。）（庭仕事が汚れた手の原因です。）
  • Don't be surprised if the team is exhausted. They will have been training non-stop for weeks before the championship.（チームが疲労困憊していても驚かないでください。彼らはチャンピオンシップの前に何週間もノンストップでトレーニングし続けているでしょう。）（疲労困憊は激しいトレーニングの結果です。）
  • 進行中の状態について確信を持って予測するため: 未来のある時点まで、ある動作が確実に期間にわたって進行していると予測するために使用できます。これはしばしば、特定​​の雰囲気や状況を暗示します。
  • Don't bother calling him at 8 PM. He will have been studying for hours and won't want a distraction.（午後8時に彼に電話しようとしないでください。彼は何時間も勉強し続けているでしょうし、邪魔されたくないでしょう。）
  • By the time the auditors arrive, we will have been shredding documents for days.（監査人が到着するまでには、私たちは何日間も書類をシュレッダーにかけていることになります。） (慌ただしい、継続的な活動の、ややユーモラスでドラマチックな予測です。)
### When Not To Use It
この時制を避けるべき時を知ることは、いつ使うべきかを知ることと同じくらい重要です。誤用は、あなたの英語を不自然で文法的に間違っているように聞こえさせる可能性があります。
  • 完了する動作に対して（結果に焦点を当てる場合）: 未来のある時点までに動作が完了した、または結果に焦点が当たっている場合は、未来完了形（Future Perfect Simple）（will have + 過去分詞）を使用してください。
  • 不適切: By 8 PM, I will have been writing the entire essay.（この文は、完了するタスクに対してプロセスを不適切に強調しています。）
  • 適切: By 8 PM, I will have written the entire essay.（結果に焦点が当たっています：エッセイは完成しているでしょう。）
  • 状態動詞（Stative Verbs）と共に: 状態動詞は、動的な動作ではなく、状態、感情、感覚、条件を記述します。それらは進行や期間を示すことができないため、どの進行形時制とも互換性がありません。一般的な例には、know、love、believe、understand、own、possess、seem、beなどがあります。
  • 不適切: By next year, I will have been knowing her for a decade.
  • 適切: By next year, I will have known her for a decade.（状態の期間には未来完了形を使用します。）
  • 不適切: In June, we will have been owning this car for three years.
  • 適切: In June, we will have owned this car for three years.
  • 期間が焦点でない場合: 特定の未来の瞬間にある動作が進行中であることを単に述べたい場合は、未来進行形（Future Continuous）（will be -ing）の方がシンプルで自然です。
  • 過度に複雑: At 3 PM tomorrow, I will have been working.（これは、for...という期間を示す句がないと不自然です。）
  • 自然: At 3 PM tomorrow, I will be working.（その正確な時間に何をしているかを述べています。）
### Common Mistakes
学習者はしばしば、この時制に関していくつかの主要な誤りを犯します。一般的な落とし穴を避けるために、これらの点に細心の注意を払ってください。
  • プロセスと完了の混同: 最も一般的な間違いは、未来完了形（Future Perfect Simple）が必要な場合にこの時制を使用することです。中心的な違いを覚えておいてください：
  • will have been doing: 期間/プロセスを強調します。動作は完了している場合も、そうでない場合もあります。
  • will have done: 完了/結果を強調します。動作は完了しています。
  • 間違い: He will have been reading the book by tomorrow.（もし彼が読み終えた場合。）
  • 訂正: He will have read the book by tomorrow.（結果：本は完成しています。）
  • 訂正: By tomorrow, he will have been reading the book for five hours.（プロセス：読書という5時間の期間を強調しています。）
  • 助動詞の欠落: will have beenという構造は長いため、単語を落としやすいです。各助動詞は不可欠です。
  • 不適切: She will have working here for a year.（beenが欠けています。）
  • 不適切: They will been practicing all day.（haveが欠けています。）
  • 適切: She will have been working here for a year.
  • 三人称でhasを使う: willは助動詞であるため、それに続く動詞（have）は変化しません。常にwill have beenであり、will has beenではありません。
  • 不適切: By 5 o'clock, he will has been waiting for an hour.
  • 適切: By 5 o'clock, he will have been waiting for an hour.
  • 未来の時間的参照がない: この時制は、未来の基準点なしには無意味です。「We will have been traveling」のような文は、「いつまで」が示されていないため、不完全です。
  • 曖昧: They will have been arguing.
  • 明確: By the time we get there, they will have been arguing for an hour.（私たちがそこに着くまでに、彼らは1時間議論し続けていることになります。）
### Contrast With Similar Patterns
どの未来時制を選択するかは、完全にあなたの焦点にかかっています。この表は、最も近い親戚である時制と比較しています。
| Tense (時制) | Structure (構造) | Focus (焦点) | Example (例文) |
|---|---|---|---|
| Future Continuous (未来進行形) | will be + -ing | 未来のある特定の瞬間における、未完了で進行中の動作。 | At 8 PM, I will be watching a movie.（午後8時、私は映画を見ています。） |
| Future Perfect Simple (未来完了形) | will have + 過去分詞 | 未来のある特定の時点までに完了した動作（結果）。 | By 8 PM, I will have watched the movie.（午後8時までに、私は映画を見終えているでしょう。） |
| Future Perfect Continuous (未来完了進行形) | will have been + -ing | 未来のある時点までの、動作の期間と継続性。 | By 8 PM, I will have been watching the movie for two hours.（午後8時までに、私は映画を2時間見続けていることになります。） |
### Quick FAQ
Q1: 未来完了進行形と未来進行形 (will be -ing) の違いは何ですか？
A1: 未来進行形は、未来のある特定の瞬間における動作の進行状況を述べます（例：At 3 PM, I will be eating lunch.）。一方、未来完了進行形は、未来のある時点までの動作の期間を強調します（例：By 3 PM, I will have been working for eight hours.）。期間が重要かどうかで使い分けます。
Q2: 未来完了進行形と未来完了形 (will have done) の違いは何ですか？
A2: 未来完了形は、未来のある時点までに動作が完了していること（結果）に焦点を当てます（例：By next week, I will have finished the report.）。未来完了進行形は、未来のある時点まで動作がどれくらいの期間続いているか（プロセス、継続性）に焦点を当てます（例：By next week, I will have been working on the report for a month.）。
Q3: 状態動詞（know, like, believeなど）で未来完了進行形は使えますか？
A3: いいえ、使えません。状態動詞は進行中の動作を表さないため、進行形とは相性が悪いです。状態の期間を未来の時点まで表したい場合は、未来完了形（will have knownなど）を使用します。
Q4: 日本語で「〜し続けているだろう」という表現は、常に未来完了進行形を使いますか？
A4: 必ずしもそうではありません。日本語では、文脈や強調したい点によって表現が変わります。未来完了進行形は、特に「どれくらいの期間」という点に焦点を当てたい場合に非常に効果的です。単に未来の時点で動作が進行中であることを示したい場合は、未来進行形 (will be -ing) を使う方が自然な場合もあります。例えば、「明日、会議で話しているだろう」は I will be talking at the meeting tomorrow. で十分ですが、「明日で、このプロジェクトについて3週間話し続けていることになるだろう」のように期間を強調したい場合は By tomorrow, I will have been talking about this project for three weeks. となります。
### 日本語学習者にとっての注意点 (Common Mistakes Specific to Japanese Speakers)
日本語話者の学習者が未来完了進行形を学ぶ上で、特に注意すべき点がいくつかあります。これらは、日本語の文法構造や思考様式が英語と異なることに起因します。
  • 「〜になるだろう」という未来の完了形との混同: 日本語では、「来年で10年になります」のように、未来のある時点での状態や経験の「完了」や「到達点」を「〜になる」と表現することがよくあります。この感覚で、英語でも完了した結果に焦点を当てがちなため、未来完了形 (will have done) を使うべき場面で未来完了進行形 (will have been doing) を使ってしまうことがあります。
  • 例：By next year, I will have been working here for 10 years.（来年で、私はここで10年間働き続けていることになります。）
  • 解説: この文は「10年間という期間」を強調しているため、未来完了進行形が適切です。しかし、もし「来年には、この会社での私の仕事は完了しているだろう」という結果を強調したいのであれば、未来完了形 By next year, I will have finished my work at this company. を使うべきです。日本語の「〜になる」という表現は、英語の will have done と will have been doing の両方に対応しうるため、文脈でどちらが適切か判断する必要があります。
  • 助動詞 will の後の have の変化: 日本語には、主語の人称や数によって動詞の形が変わるという概念が、英語ほど厳密ではありません。しかし、英語では will の後には常に原形不定詞 have が来ます。三人称単数現在形のように has になることはありません。日本語話者は、つい主語に合わせて will has been のように間違えやすい傾向があります。
  • 間違い: He will has been studying.
  • 正しい: He will have been studying.
  • 解説: will は未来を示す助動詞であり、その後に続く動詞は常に原形です。これは will be や will do と同じルールです。has は三人称単数現在の形ですが、will の後では使われません。
  • 「〜している」という進行形との混同: 日本語の「〜している」は、現在進行形、現在完了進行形、あるいは単なる状態を表す場合など、幅広い意味を持ちます。未来完了進行形も「〜し続けているだろう」と訳されるため、単純な未来進行形 (will be -ing) との区別が曖昧になりがちです。未来進行形は未来のある一点での動作の進行を表しますが、未来完了進行形は未来のある時点までの「期間」を強調します。
  • 間違い: Tomorrow at noon, I will have been eating lunch.（明日の正午に、私は昼食を食べ続けていることになります。）
  • 正しい: Tomorrow at noon, I will be eating lunch.（明日の正午、私は昼食を食べているでしょう。）
  • 解説: 明日の正午に「昼食を食べている」というその瞬間の状況を述べたいのであれば、未来進行形が適切です。もし「明日の正午で、昼食を食べるのに1時間かかっていることになるだろう」のように期間を強調したいなら、By noon tomorrow, I will have been eating lunch for an hour. となります。日本語の「〜しているだろう」が、どの時点での進行か、あるいは期間の継続かによって、英語の時制を慎重に選ぶ必要があります。
  • 期間を示す for や since の欠如: 未来完了進行形は、通常、期間を示す for（〜の間）や、文脈から期間が明らかな場合に用いられます。期間が不明確なままこの時制を使うと、不自然に聞こえることがあります。日本語では期間を省略しても意味が通じる場合が多いですが、英語では、特にこの時制では期間の明示が重要になります。
  • 曖昧: We will have been waiting.
  • 明確: By the time the train arrives, we will have been waiting for two hours.（電車が到着するまでに、私たちは2時間待っていることになります。）
  • 解説: 日本語話者は、期間を明示せずに「待っているだろう」というニュアンスでこの時制を使ってしまうことがありますが、英語では期間の明示が、この時制の意図を正確に伝えるために不可欠です。
### Memory Trick
この時制の機能と構造を覚えるために、「未来の回顧（Future Retrospective）」というメンタルイメージを使用してください。未来のある時点（例：「新年」「プロジェクトの締め切り」）に自分が立っていると想像してください。そのチェックポイントから、動作を表す継続的な道（road）を振り返っています。
  • 未来のチェックポイント: will
  • 振り返る: have been
  • 継続的な道: -ing
構造については、will + have + been + verb-ing という公式を覚えてください。これら4つの要素は常にその順序でなければなりません。
### Real Conversations
この時制は、特に計画、締め切り、あるいは不満について議論する際に、実際の会話で現れます。時間の経過と努力に重点を置くことで、表現に深みが加わります。
仕事のメール:
> Subject: Project Apollo - Status Check
> Hi team, just a reminder that the deadline is next Friday. By then, we will have been working on this phase for six straight weeks, so let's make sure we're on track to deliver.
> （チーム各位、来週金曜日が締め切りであることを思い出してください。その時点までに、私たちはこのフェーズに6週間連続で取り組んでいることになりますので、予定通り進められるようにしましょう。）
友人にテキストメッセージ:
> Friend A: ETA 20 mins, traffic is insane!
> Friend B: Dude, by the time you get here I 'll have been waiting for nearly an hour! Hurry up!
> （A: あと20分で着く、道がひどい！ B: おい、お前が着く頃には俺、1時間近く待ってることになるぞ！急げ！）
日常会話:
> "It's amazing to think that in just two more years, Professor Evans will have been teaching at this university for half a century."
> （「あとわずか2年で、エバンス教授はこの大学で半世紀も教え続けていることになるなんて、すごいことですね。」）

Conjugation of 'To Work' in Future Perfect Continuous

Subject Auxiliary Perfect/Continuous Main Verb (-ing)
I
will
have been
working
You
will
have been
working
He/She/It
will
have been
working
We
will
have been
working
They
will
have been
working

Contractions and Short Forms

Full Form Contraction Negative Contraction
I will have been
I'll have been
I won't have been
You will have been
You'll have been
You won't have been
He will have been
He'll have been
He won't have been
We will have been
We'll have been
We won't have been
They will have been
They'll have been
They won't have been

Meanings

The Future Perfect Continuous describes an ongoing action that will continue up until a specific point in the future, focusing specifically on the duration or the process of that action.

1

Duration up to a future point

To show how long an activity has been in progress when a future deadline is reached.

“By the time the sun sets, we will have been hiking for eight hours straight.”

“In December, she will have been working at this firm for two decades.”

2

Cause of a future result

To explain the reason for a future state or feeling based on a continuous action.

“I'll be exhausted when I see you because I will have been traveling for 24 hours.”

“Their eyes will be tired because they will have been staring at screens all day.”

3

Projected certainty of duration

Expressing a strong conviction about the length of an ongoing future state.

“By then, they will have been dating long enough to get married.”

“I will have been practicing this piece so much that I'll know it by heart.”

Reference Table

Reference table for 未来完了進行形：継続の時制
Form Structure Example
Affirmative
S + will + have + been + V-ing
I will have been running.
Negative
S + will + not + have + been + V-ing
She won't have been studying.
Question
Will + S + have + been + V-ing?
Will they have been waiting?
Short Answer (+)
Yes, S + will.
Yes, I will.
Short Answer (-)
No, S + won't.
No, they won't.
Wh- Question
Wh- + will + S + have + been + V-ing?
How long will you have been driving?

フォーマル度スペクトル

フォーマル
By the conclusion of this fiscal year, Mr. Smith will have been serving as Director for a decade.

By the conclusion of this fiscal year, Mr. Smith will have been serving as Director for a decade. (Professional milestone)

ニュートラル
By the end of the year, he will have been working as the Director for ten years.

By the end of the year, he will have been working as the Director for ten years. (Professional milestone)

カジュアル
He'll have been the boss for ten years by Christmas.

He'll have been the boss for ten years by Christmas. (Professional milestone)

スラング
He's gonna have been running the show for ten years straight soon.

He's gonna have been running the show for ten years straight soon. (Professional milestone)

The Anatomy of the Future Perfect Continuous

Future Perfect Continuous

Components

  • Will Future marker
  • Have Perfect marker
  • Been Continuous marker
  • Verb-ing Action

Time Markers

  • By... The deadline
  • For... The duration

Continuous vs. Perfect Continuous

Future Continuous
I will be working Focus on the moment
Future Perfect Continuous
I will have been working for 5 hours Focus on the duration
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レベル別の例文

1

I will have been here for one hour.

I will have been here for one hour.

2

She will have been sleeping for a long time.

She will have been sleeping for a long time.

3

We will have been playing for ten minutes.

We will have been playing for ten minutes.

4

Will you have been waiting long?

Will you have been waiting long?

1

By 6 PM, I will have been working for eight hours.

By 6 PM, I will have been working for eight hours.

2

They will have been living here for a month soon.

They will have been living here for a month soon.

3

He won't have been studying for very long.

He won't have been studying for very long.

4

How long will she have been cooking by then?

How long will she have been cooking by then?

1

By the time the train arrives, we will have been standing here for forty minutes.

By the time the train arrives, we will have been standing here for forty minutes.

2

Next year, they will have been traveling around the world for six months.

Next year, they will have been traveling around the world for six months.

3

I will have been practicing the piano all day, so I'll be tired.

I will have been practicing the piano all day, so I'll be tired.

4

Will you have been staying at the hotel for a week by Friday?

Will you have been staying at the hotel for a week by Friday?

1

By the end of this semester, I will have been researching this topic for over a year.

By the end of this semester, I will have been researching this topic for over a year.

2

She will have been competing professionally for a decade by the time she retires.

She will have been competing professionally for a decade by the time she retires.

3

They won't have been dating long enough to make such a big decision.

They won't have been dating long enough to make such a big decision.

4

By tomorrow morning, it will have been snowing for twenty-four hours straight.

By tomorrow morning, it will have been snowing for twenty-four hours straight.

1

By the time the legislation passes, the committee will have been debating its merits for years.

By the time the legislation passes, the committee will have been debating its merits for years.

2

I'll be quite relieved when the project ends, as I will have been working under immense pressure.

I'll be quite relieved when the project ends, as I will have been working under immense pressure.

3

Will the scientists have been monitoring the volcano long enough to predict the eruption?

Will the scientists have been monitoring the volcano long enough to predict the eruption?

4

By the gala, the dancers will have been rehearsing this specific choreography for months.

By the gala, the dancers will have been rehearsing this specific choreography for months.

1

Upon his inauguration, he will have been campaigning tirelessly for the better part of two years.

Upon his inauguration, he will have been campaigning tirelessly for the better part of two years.

2

The ecosystem will have been recovering from the spill for decades before it reaches its former state.

The ecosystem will have been recovering from the spill for decades before it reaches its former state.

3

By the time the sun burns out, it will have been fusing hydrogen for billions of years.

By the time the sun burns out, it will have been fusing hydrogen for billions of years.

4

One wonders if they will have been cohabiting in such disharmony for long before they part ways.

One wonders if they will have been cohabiting in such disharmony for long before they part ways.

間違えやすい

Future Perfect Continuous: The Duration Tense 対 Future Continuous

Both tenses use 'will' and '-ing'. Learners often use Future Continuous when they should be measuring duration.

Future Perfect Continuous: The Duration Tense 対 Future Perfect Simple

Learners struggle to choose between the result (Simple) and the process (Continuous).

Future Perfect Continuous: The Duration Tense 対 Present Perfect Continuous

The structures are similar (have been -ing).

よくある間違い

✗

I will have working.

✓

I will have been working.

You missed the word 'been'.
✗

I will been working.

✓

I will have been working.

You missed the word 'have'.
✗

I will have been work.

✓

I will have been working.

You need the -ing form for continuous tenses.
✗

By tomorrow I will have been here.

✓

By tomorrow I will have been staying here.

The continuous form needs an action verb.
✗

I will have been knowing him.

✓

I will have known him.

'Know' is a stative verb and cannot be continuous.
✗

Will you have been work?

✓

Will you have been working?

Questions still need the -ing form.
✗

I won't have been wait long.

✓

I won't have been waiting long.

Negative forms also require -ing.
✗

By the time he comes, I will be working for 2 hours.

✓

By the time he comes, I will have been working for 2 hours.

Use Future Perfect Continuous for duration up to a point, not Future Continuous.
✗

I will have been being tired.

✓

I will have been tired.

Adjectives like 'tired' use the Simple form, not Continuous.
✗

How long will you have been having this car?

✓

How long will you have had this car?

Possession 'have' is stative.
✗

By next year, the house will have been being built.

✓

By next year, the house will have been under construction.

The passive of this tense is so rare it sounds unnatural; use a prepositional phrase instead.

文型パターン

By the time ___, I will have been ___ for ___.

In [Month/Year], she will have been ___ at ___ for ___.

Real World Usage

Job Interviews common

By next month, I will have been working in this industry for five years.

Anniversaries very common

On Saturday, we will have been dating for exactly two years!

Project Management common

By the time we launch, the developers will have been coding for six months.

Travel Planning occasional

By the time we reach Tokyo, we will have been traveling for 15 hours.

Academic Writing occasional

The subjects will have been receiving the treatment for three weeks before the first evaluation.

Weather Forecasts occasional

By tomorrow, it will have been raining for three days straight.

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💡

The 'For' Rule

If you are using 'for' to describe a duration in the future, check if you need the Future Perfect Continuous. It's the most reliable signal.
⚠️

Stative Verb Alert

Never use 'being', 'knowing', 'loving', or 'having' (possession) in this tense. Use the Future Perfect Simple instead.
🎯

Simplify in Speech

In fast conversation, native speakers often use the Future Continuous ('I'll be working') even when they mean the Perfect Continuous. Don't panic if you hear this!
💬

Emphasis

Use this tense when you want to complain about how long something is taking. It makes the duration sound more impressive.

Smart Tips

Use the Future Perfect Continuous to describe your upcoming milestones.

Next year, I will work here for five years. → By next year, I will have been working here for five years.

Use this tense to emphasize the exhaustion of travel.

When we get to Sydney, we will travel for 20 hours. → By the time we reach Sydney, we will have been traveling for 20 hours.

Immediately check if you need 'will have been -ing'.

I will be waiting for you for two hours. → I will have been waiting for you for two hours.

Switch to Future Perfect Simple immediately.

I will have been liking this book. → I will have liked this book.

発音

/aɪl əv bɪn/

The 'will have' contraction

In natural speech, 'will have' is almost always contracted to 'll have' or even 'll've'.

/bɪn/

The weak 'been'

The word 'been' is usually unstressed and pronounced with a short /ɪ/ sound, like 'bin'.

Emphasis on duration

I will have been waiting for FIVE hours!

The speaker is emphasizing the length of time to show frustration or effort.

暗記しよう

記憶術

W.H.B.I. - 'Will Have Been -Ing'. Think: 'Will He Be Interesting?' to remember the order of the auxiliary verbs.

視覚的連想

Imagine a long, glowing bridge stretching from today into next year. At the end of the bridge is a clock. The bridge represents the 'duration' (have been -ing) and the clock is the 'future point' (will).

Rhyme

By the time the clock strikes ten, I will have been working since who knows when!

Story

A marathon runner is approaching the finish line. As they run, they think: 'By the time I cross that line, I will have been running for four hours.' The line is the future point, and the sweat is the continuous effort.

Word Web

DurationProcessMilestoneAnniversaryContinuityDeadlineProjection

チャレンジ

Write down one thing you will have been doing for a long time by the end of this year. Use the full structure: 'By December 31st, I will have been...'

文化メモ

British speakers may use 'shall' instead of 'will' in very formal contexts, though 'shall have been' is becoming extremely rare.

Americans often simplify this tense in casual conversation, opting for the Future Continuous if the duration is already clear from the context.

This tense is frequently used in performance reviews and project planning to emphasize commitment and long-term involvement.

The English future perfect continuous developed as the language moved from a synthetic structure (using endings) to an analytic structure (using auxiliary verbs).

会話のきっかけ

“

By the end of this year, how long will you have been studying English?

“

If you stay in your current job for another five years, how long will you have been working there in total?

“

By the time you retire, what is one hobby you will have been doing for most of your life?

“

Imagine you are on a 20-hour flight. By the 15th hour, how will you be feeling and what will you have been doing?

日記のテーマ

Write about your 10-year high school reunion. Describe what you will have been doing since graduation.
Describe a long-term scientific experiment. Explain what the scientists will have been monitoring by the time the results are published.
Write a letter to your future self 5 years from now. Mention the habits you hope you will have been maintaining.
Predict the state of the environment in 2050. What processes will have been occurring for decades?

よくある間違い

Incorrect

正解

Incorrect

正解

Incorrect

正解

Incorrect

正解

Sign up free to see all tips

Test Yourself

Complete the sentence with the correct form of the verb in parentheses.

By the time the guest arrives, I ___ (cook) for three hours.

✓ Correct! ✗ Not quite. Correct answer: will have been cooking
We need the Future Perfect Continuous to show the duration (three hours) up to a future point.
Identify the error in the sentence. Error Correction

Find and fix the mistake:

By next week, she will has been living here for a month.

✓ Correct! ✗ Not quite. Correct answer: will has
After 'will', we must use the base form 'have', never 'has'.
Choose the best tense for the context. 選択問題

I'm so tired! By the time I get home, I ___ for ten hours.

✓ Correct! ✗ Not quite. Correct answer: will have been working
The context emphasizes the duration and the cause of tiredness.
Change the sentence to the Future Perfect Continuous. Sentence Transformation

I am studying English. (By 2026 / for five years)

✓ Correct! ✗ Not quite. Correct answer: By 2026, I will have been studying English for five years.
This correctly combines the future point and the duration.
Is the following sentence grammatically correct? True False Rule

By next year, I will have been knowing her for a decade.

✓ Correct! ✗ Not quite. Correct answer: False
'Know' is a stative verb and cannot be used in the continuous form.
Complete the dialogue. Dialogue Completion

A: Will you be tired when you arrive? B: Yes, I ___ for two days.

✓ Correct! ✗ Not quite. Correct answer: will have been traveling
The duration 'for two days' explains the state of being tired.
Which of these verbs CANNOT be used in the Future Perfect Continuous? Grammar Sorting

✓ Correct! ✗ Not quite. Correct answer: Understand
'Understand' is a stative verb.
Match the start of the sentence with the correct ending. Match Pairs

Match each item on the left with its pair on the right:

✓ Correct! ✗ Not quite. Correct answer: 1. I will have been sleeping for 2 hours. / 2. I will have been working here for a year. / 3. I will have been waiting for an hour.
These all correctly use the future perfect continuous structure.

Score: /8

練習問題

8 exercises
Complete the sentence with the correct form of the verb in parentheses.

By the time the guest arrives, I ___ (cook) for three hours.

✓ Correct! ✗ Not quite. Correct answer: will have been cooking
We need the Future Perfect Continuous to show the duration (three hours) up to a future point.
Identify the error in the sentence. Error Correction

Find and fix the mistake:

By next week, she will has been living here for a month.

✓ Correct! ✗ Not quite. Correct answer: will has
After 'will', we must use the base form 'have', never 'has'.
Choose the best tense for the context. 選択問題

I'm so tired! By the time I get home, I ___ for ten hours.

✓ Correct! ✗ Not quite. Correct answer: will have been working
The context emphasizes the duration and the cause of tiredness.
Change the sentence to the Future Perfect Continuous. Sentence Transformation

I am studying English. (By 2026 / for five years)

✓ Correct! ✗ Not quite. Correct answer: By 2026, I will have been studying English for five years.
This correctly combines the future point and the duration.
Is the following sentence grammatically correct? True False Rule

By next year, I will have been knowing her for a decade.

✓ Correct! ✗ Not quite. Correct answer: False
'Know' is a stative verb and cannot be used in the continuous form.
Complete the dialogue. Dialogue Completion

A: Will you be tired when you arrive? B: Yes, I ___ for two days.

✓ Correct! ✗ Not quite. Correct answer: will have been traveling
The duration 'for two days' explains the state of being tired.
Which of these verbs CANNOT be used in the Future Perfect Continuous? Grammar Sorting

✓ Correct! ✗ Not quite. Correct answer: Understand
'Understand' is a stative verb.
Match the start of the sentence with the correct ending. Match Pairs

1. By midnight... / 2. By next year... / 3. By the time he arrives...

✓ Correct! ✗ Not quite. Correct answer: 1. I will have been sleeping for 2 hours. / 2. I will have been working here for a year. / 3. I will have been waiting for an hour.
These all correctly use the future perfect continuous structure.

Score: /8

Practice Bank

12 exercises
Complete the sentence with the Future Perfect Continuous. 穴埋め問題

By midnight, the band ___ (perform) for five hours straight.

✓ Correct! ✗ Not quite. Correct answer: will have been performing
Identify and correct the grammatical error. Error Correction

When we meet, I will have waited for over twenty minutes.

✓ Correct! ✗ Not quite. Correct answer: When we meet, I will have been waiting for over twenty minutes.
Select the sentence that uses the Future Perfect Continuous correctly. 選択問題

Which sentence is grammatically correct?

✓ Correct! ✗ Not quite. Correct answer: By 2030, scientists will have known how to cure this disease for years.
Translate the sentence into English using the Future Perfect Continuous. 翻訳

Translate into English: 'Para cuando termine la obra, habrán estado construyendo el edificio por tres años.'

✓ Correct! ✗ Not quite. Correct answer: ["By the time the work finishes, they will have been building the building for three years.","By the time the project is complete, they'll have been constructing the building for three years."]
Arrange the words to form a correct sentence using the Future Perfect Continuous. Sentence Reorder

Put the words in order:

✓ Correct! ✗ Not quite. Correct answer: By 5PM, she will have been reading at the Library for three hours.
Match the subject with the correct auxiliary verb phrase for the Future Perfect Continuous. Match Pairs

Match the subjects with the correct form:

✓ Correct! ✗ Not quite. Correct answer: matched
Complete with the correct Future Perfect Continuous form. 穴埋め問題

If you don't call soon, I ___ (worry) about you for hours by now.

✓ Correct! ✗ Not quite. Correct answer: will have been worrying
Correct the error in the sentence. Error Correction

By Tuesday, we will have been travel for a week.

✓ Correct! ✗ Not quite. Correct answer: By Tuesday, we will have been traveling for a week.
Which sentence is the best fit for Future Perfect Continuous? 選択問題

Choose the best option:

✓ Correct! ✗ Not quite. Correct answer: By Christmas, I will have been decorating the entire house for a month.
Translate into English: 'El próximo año, ella habrá estado trabajando como enfermera durante diez años.' 翻訳

Translate into English: 'El próximo año, ella habrá estado trabajando como enfermera durante diez años.'

✓ Correct! ✗ Not quite. Correct answer: ["Next year, she will have been working as a nurse for ten years.","By next year, she'll have been working as a nurse for ten years."]
Unscramble the words to form a coherent sentence. Sentence Reorder

Arrange these words into a sentence:

✓ Correct! ✗ Not quite. Correct answer: By the meeting's start, they will have been discussing the topic for hours.
Fill in the blank with the correct verb form. 穴埋め問題

By the time the festival ends, I ___ (dance) for almost twelve hours!

✓ Correct! ✗ Not quite. Correct answer: will have been dancing

Score: /12

よくある質問 (8)

No, it is quite rare. Most native speakers will use the Future Continuous or Future Perfect Simple unless they specifically want to emphasize the duration of an action.

Yes, but only with 'I' and 'we', and it sounds extremely formal or old-fashioned. 'I shall have been working' is grammatically correct but rarely heard.

We use `by` to indicate the deadline or the point in time we are looking back from. We use `until` to show when the action stops. Example: 'By 5:00, I will have been working until I can't see straight.'

Yes, but remember that after 'when', we use the present tense to refer to the future. Example: 'When you arrive, I will have been waiting for an hour.'

Because 'know' is a stative verb. Stative verbs describe states, not actions, and English grammar generally forbids using them in any continuous (-ing) tense.

Technically, yes: 'will have been being + past participle'. However, it is so awkward that native speakers almost never use it. Instead of 'The car will have been being repaired for a week', we say 'The car will have been in the shop for a week'.

You can say 'Won't you have been working?' or 'Will you not have been working?'. The first is much more common in spoken English.

Almost always. Without a time expression like 'for two hours' or 'since morning', the tense loses its primary purpose of showing duration.

Scaffolded Practice

1

1

2

2

3

3

4

4

Mastery Progress

Needs Practice

Improving

Strong

Mastered

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In Other Languages

Spanish high

Futuro perfecto + gerundio

English always uses 'will have been', while Spanish has alternative verbs for duration.

French low

Futur antérieur + en train de

French avoids the continuous aspect in the future perfect.

German moderate

Futur II

German lacks a specific continuous form for the future perfect.

Japanese low

~te iru koto ni naru

Japanese focuses on the state/result rather than the auxiliary string 'will have been'.

Arabic partial

sa + yakun + qad + kuntu

Arabic uses aspectual particles rather than a single continuous verb form.

Chinese none

yijing ... le

Chinese relies entirely on context and time adverbs.

Learning Path

Prerequisites

Previous
予定された未来 (～することになっている, ～する予定である)
Next
Future in the Past: Was Going To, Would, Was About To

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