Grammar Rule in 30 Seconds
Use 'Modal + have + been + Past Participle' to discuss past events where the focus is on the receiver, not the doer.
- Use 'should have been' for past regrets or missed opportunities (e.g., 'It should have been fixed').
- Use 'must have been' for strong logical deductions about the past (e.g., 'The window must have been broken').
- Use 'could have been' for past possibilities that didn't happen (e.g., 'The game could have been won').
Overview
Passive Perfect Modals（助動詞＋完了形＋受動態：must have been done など）は、まさにその代表格と言えるでしょう。この形は、単に「過去に何かが起きた」という事実を述べるのではなく、その過去の出来事に対して「推量」「後悔」「可能性」「義務」といった話し手の主観的な判断を、受動態の視点から加えるための非常に高度な表現です。You should have checked it）よりも、「そのデータは確認されるべきだった」（The data should have been checked）と言う方が、客観的でプロフェッショナルな響きになります。このように、責任の所在を和らげたり、あるいは証拠に基づいた論理的な推論を展開したりする際に、この文法は欠かせないツールとなります。must や should といった助動詞のニュアンスと、have + 過去分詞 という完了形の時間軸が加わるため、頭の中で組み立てるのに時間がかかってしまいがちです。本講義では、この複雑な構造を分解し、ネイティブスピーカーがどのような感覚でこれらの言葉を選んでいるのか、その核心に迫ります。- 1助動詞 (Modal Verbs): 話し手の態度や確信度を表します（
must,should,could,mightなど）。 - 2完了形 (Perfect Aspect):
have + 過去分詞の形で、「過去の時点」に焦点を当てます。助動詞の直後に来るため、haveは常に原形です。 - 3受動態 (Passive Voice):
be + 過去分詞の形で、「〜される」という受け身の意味を作ります。完了形と組み合わさるため、beは過去分詞のbeenに固定されます。
Modal + have been + Past Participle (V3) という形が出来上がります。日本語の文法体系と比較してみましょう。must have been done | 〜されたに違いない | 過去の事実に対する強い確信（証拠あり） |should have been done | 〜されるべきだった（が、されなかった） | 過去の義務や期待に対する後悔・非難 |could have been done | 〜される可能性があった / 〜され得た | 実現しなかった過去の可能性 |might have been done | 〜されたかもしれない | 過去の出来事に対する低い確信・推測 |Modal + have been + V3 というパッケージを一つのユニットとして脳内に定着させることが、C1レベルの流暢さへの近道です。The meeting room should have been reserved のように、必ず The meeting room を主語に据える必要があります。have は主語が三人称単数であっても has にはならないということです。助動詞の直後は常に動詞の原形という鉄則があるため、He must have been... となり、He must has been... とは決して言いません。- 肯定文 (Affirmative):
The package must have been delivered yesterday.（荷物は昨日届けられたに違いない。）The mistake could have been prevented.（そのミスは防げたはずだ。）
- 否定文 (Negative):
notは助動詞の直後に置きます。 The sensitive data should not have been shared.（機密データは共有されるべきではなかった。）It couldn't have been stolen by him.（それが彼に盗まれたはずがない。）
- 疑問文 (Interrogative): 助動詞を文頭に出します。
Could the project have been completed sooner?（プロジェクトはもっと早く完了できただろうか？）Should the client have been informed earlier?（クライアントにはもっと早く知らせるべきだったのでしょうか？）
must have been + V3: 「〜されたに違いない」- 客観的な証拠に基づいた、ほぼ100%に近い確信。
can't/couldn't have been + V3: 「〜されたはずがない」mustの否定的な推論。強い確信を持って否定する場合。should have been + V3: 「〜されるべきだった（のに実際はされなかった）」- 後悔、あるいは他者への批判・アドバイス。
may/might have been + V3: 「〜されたかもしれない」- 50%以下の低い確信度。不確かな推測。
would have been + V3: 「（もし〜だったら）〜されていただろう」- 仮定法過去完了。実際には起きなかった「もしも」の話。
My PC must have been replaced over the weekend.
must）を込めています。I feel that more research should have been done before the interview.
research を主語にすることで、自分の行動を客観的に分析している印象を与えます。日本の「反省」の文化に非常に馴染む表現です。The crisis could have been avoided if we had reacted faster.
The error should have been caught during the double-check process.
been の脱落（能動態と受動態の混同）have + V3（能動完了）と have been + V3（受動完了）を混同してしまいます。- ❌ Incorrect:
The report should have finished by 5 PM. - ⭕ Correct:
The report should have been finished by 5 PM.
been がないと、レポートが自ら意思を持って何かを終わらせたことになってしまいます。must と should の使い分けミス- ❌ Incorrect:
The lights are on. He should have been home. - ⭕ Correct:
The lights are on. He must have been home.
must を使います。should を使うと「彼は家にいるべきだった（のにいなかった）」という非難や後悔の意味になってしまいます。has への書き換え- ❌ Incorrect:
The document must has been sent. - ⭕ Correct:
The document must have been sent.
The document なので has にしたくなりますが、助動詞 must の後ろは常に原形 have です。これは中学レベルの知識ですが、文が長くなると上級者でもうっかり間違えてしまうポイントです。- ❌ Incorrect:
The car should have been not parked here. - ⭕ Correct:
The car should not have been parked here.
not は必ず「最初の助動詞」の直後に置きます。日本語の「〜されるべきではなかった」という語順に引っ張られないようにしましょう。He should have fixed it. | 彼がそれを直すべきだった（彼の責任に焦点） |It should have been fixed. | それは直されるべきだった（物の状態に焦点） |It should be fixed. | それは（今）直されるべきだ（現在の義務） |It should have been fixed. | それは（過去に）直されるべきだった（過去の後悔） |It was fixed. | それは直された（単なる過去の事実） |It must have been fixed. | それは直されたに違いない（過去の事実への推論） |Passive Perfect Modal は「過去」の出来事に対して、話し手が「今」どう感じているか、あるいはどう推論しているかという、時間軸の交差を表現しています。could have been done と might have been done はどう使い分けますか？could は「能力的に〜し得た（でもしなかった）」というニュアンスや、より論理的な可能性を指すことが多いです。一方、might は「ひょっとしたら〜だったかもしれない」という、より確信度の低い、単なる推測の響きが強くなります。例えば、犯罪捜査で「彼が犯人だった可能性もある」という時は He could have been the killer（論理的可能性）や He might have been the killer（不確かな推測）の両方が使えますが、文脈によって確信の度合いが変わります。should have been done を使うと失礼になりますか？You should have done... と言うのは非常に攻撃的ですが、The documents should have been attached to the previous email.（前のメールに書類が添付されているべきでした＝添付されていませんでしたよ）と言うのは、事実を述べる丁寧な指摘として機能します。ただし、目上の人に対して使う場合は、It seems that the documents were not attached... のように、より間接的な表現を好むネイティブもいます。must have been done は「〜されなければならなかった」という意味にはなりますか？must を「義務（〜しなければならない）」の意味で過去形で使いたい場合は、had to be done を使います。must have been done は、あくまで「過去の推量（〜されたに違いない）」という、話し手の確信を表す表現です。ここが英語の助動詞の非常にトリッキーな部分です。Passive Perfect Modals を使いこなすためには、まず「日本語の受身」の感覚を一度捨てることが大切です。英語の受動態は、単なる「被害」ではなく、情報の整理術です。電車の中で「この車両、最近掃除されたのかな？」と思ったら Must this carriage have been cleaned recently? と頭の中で唱えてみたり、コンビニで「お弁当の割り箸が入っていなかった」という時に Chopsticks should have been put in the bag. と考えてみたりしてください。Modal + have been + V3）に当てはめる練習を繰り返すことで、C1レベルにふさわしい、深みのある英語表現が自然と口から出るようになるはずです。頑張りましょう（Keep up the great effort!）Passive Perfect Modal Structure
| Subject | Modal | Perfect Auxiliary | Passive Marker | Past Participle |
|---|---|---|---|---|
|
The car
|
must
|
have
|
been
|
stolen
|
|
The letters
|
should
|
have
|
been
|
sent
|
|
The problem
|
could
|
have
|
been
|
solved
|
|
The law
|
might
|
have
|
been
|
changed
|
|
The truth
|
may
|
have
|
been
|
hidden
|
|
The work
|
ought to
|
have
|
been
|
done
|
Common Contractions
| Full Form | Contraction | Pronunciation Note |
|---|---|---|
|
should have been
|
should've been
|
Sounds like 'should-uv-bin'
|
|
could have been
|
could've been
|
Sounds like 'could-uv-bin'
|
|
must have been
|
must've been
|
Sounds like 'must-uv-bin'
|
|
might have been
|
might've been
|
Sounds like 'might-uv-bin'
|
Meanings
A grammatical structure used to express degrees of certainty, obligation, or regret about past actions while maintaining a passive focus on the object of the action.
Logical Deduction
Expressing a strong belief that something happened based on evidence.
“The safe must have been opened with a key.”
“The lights were on, so the house must have been cleaned already.”
Unfulfilled Obligation/Regret
Expressing that an action was desirable or necessary but did not occur.
“The report should have been submitted yesterday.”
“The guests ought to have been informed of the delay.”
Past Possibility
Discussing things that were possible in the past but did not happen, or whose occurrence is uncertain.
“The package could have been lost in the mail.”
“The building might have been saved if the fire department arrived sooner.”
Reference Table
| モーダル | 意味 | 例文（能動態） | 例文（受動態） |
|---|---|---|---|
|
must
|
強い確信／推測
|
He must have taken it.
|
It must have been taken.
|
|
might
|
可能性／不確実性
|
She might have forgotten.
|
It might have been forgotten.
|
|
could
|
過去の可能性／機会
|
They could have warned us.
|
We could have been warned.
|
|
should
|
後悔／過去の義務
|
You should have told me.
|
I should have been told.
|
|
would
|
仮定（過去）
|
I would have seen it.
|
It would have been seen.
|
フォーマル度スペクトル
The error should have been circumvented through more rigorous oversight. (Discussing a failure.)
The mistake should have been avoided. (Discussing a failure.)
That shouldn't have happened. (Discussing a failure.)
That was a total fail, shouldn've been like that. (Discussing a failure.)
受動態完了形モーダル：あなたのタイムトラベルツールキット
構造
- Modal + have been + V3 主語が行動を受け、過去に完了
- Modal Verbs must, might, could, should, would
使用シナリオ
- 過去の推測 強い確信（must have been）
- 過去の可能性 不確実性（might/could have been）
- 過去の後悔／批判 未達成の義務（should have been）
- 仮定の過去 仮定法タイプ3（would have been）
よくある間違い
- 「been」の欠落 受動態に必須
- 能動態と受動態 主語が行ったか、受けたか
- 間違ったモーダル 意味が変わる（must vs should）
モーダル完了形対決：能動態 vs. 受動態
受動態完了形モーダルの選び方
過去にその行動は完了しましたか？
主語はその行動を「受けて」いますか？
強い推測や確信を表現していますか？
後悔、批判、または未達成の義務を表現していますか？
可能性や不確実性を表現していますか？
仮定の過去（「もし～ならば」といった文脈）を説明していますか？
過去の受動的行動のためのモーダルメニュー
高い確信
- • must have been finished
- • must have been reported
低い確信／可能性
- • might have been forgotten
- • could have been stolen
後悔／義務
- • should have been done
- • should have been said
仮定の過去
- • would have been prevented
- • would have been accepted
レベル別の例文
The door must have been locked.
La puerta debe haber estado cerrada.
The food must have been good.
La comida debe haber estado buena.
It must have been cold.
Debió haber hecho frío.
The car must have been red.
El coche debe haber sido rojo.
The homework should have been done.
La tarea debería haber sido hecha.
The window could have been broken.
La ventana podría haber sido rota.
The lights should have been turned off.
Las luces deberían haber sido apagadas.
The cat must have been fed.
El gato debe haber sido alimentado.
The meeting might have been cancelled.
La reunión podría haber sido cancelada.
The project should have been finished by now.
El proyecto debería haber sido terminado ya.
The keys must have been left in the car.
Las llaves deben haber sido dejadas en el coche.
The cake couldn't have been eaten by the dog.
El pastel no pudo haber sido comido por el perro.
The documents ought to have been filed correctly.
Los documentos deberían haber sido archivados correctamente.
The suspect must have been seen by someone.
El sospechoso debe haber sido visto por alguien.
The error should never have been allowed to happen.
El error nunca debería haber sido permitido que ocurriera.
The city could have been destroyed by the storm.
La ciudad podría haber sido destruida por la tormenta.
The implications of the policy must have been overlooked.
Las implicaciones de la política deben haber sido pasadas por alto.
The manuscript might have been written by a different author.
El manuscrito podría haber sido escrito por un autor diferente.
The funds should have been allocated to education instead.
Los fondos deberían haber sido asignados a la educación en su lugar.
The witness may have been intimidated into silence.
El testigo puede haber sido intimidado para guardar silencio.
Had the warnings been heeded, the tragedy might have been averted.
Si se hubieran escuchado las advertencias, la tragedia podría haberse evitado.
The nuances of the text could not have been fully grasped without context.
Los matices del texto no podrían haber sido captados completamente sin contexto.
It is argued that the treaty should have been ratified much earlier.
Se argumenta que el tratado debería haber sido ratificado mucho antes.
The artifacts must have been meticulously preserved for centuries.
Los artefactos deben haber sido preservados meticulosamente durante siglos.
間違えやすい
Learners mix up 'should have been done' with 'had been done'.
Both express necessity, but 'must have been' is for logical deduction.
Learners use 'could have been' for things that actually happened.
よくある間違い
It must been done.
It must have been done.
The car must have done.
The car must have been done.
He must has been seen.
He must have been seen.
It should have be done.
It should have been done.
The window should have broken.
The window should have been broken.
Could it have be stolen?
Could it have been stolen?
It must have been stole.
It must have been stolen.
The work must had been finished.
The work must have been finished.
It shouldn't have been happen.
It shouldn't have happened.
The cake must have being eaten.
The cake must have been eaten.
The report ought to been sent.
The report ought to have been sent.
It might have been being repaired.
It might have been under repair.
The money must have been disappeared.
The money must have disappeared.
It should have been done by now.
It should have been done by then.
文型パターン
The ___ must have been ___ by ___.
It should have been ___ much ___.
Under no circumstances should the ___ have been ___.
Could the ___ have been ___ differently?
Real World Usage
In my last role, the workflow could have been better organized.
That party must've been lit!
The entry must have been forced from the outside.
This video should've been edited better.
The pizza should have been delivered hot.
The data might have been influenced by external variables.
「been」を見つける
The report must have been submitted.
能動態 vs. 受動態の罠
The thief might have been caught by the police.
後悔を強調する表現
The mistake should have been avoided.
ニュースにおけるニュアンス
The decision must have been made by a committee.
確信度を確認する
The key could have been left on the table.
Smart Tips
Use the passive 'should have been' to focus on the task, not the person who failed.
Use 'must have been' to sound like a detective.
Avoid 'I think' and use 'It might have been' to sound more objective.
Remember it's actually 'should have'. Don't let native slang ruin your grammar!
発音
The 'Schwa' in 'have'
In natural speech, 'have' is almost never stressed. It reduces to /əv/.
The 'been' reduction
The word 'been' is often pronounced with a short 'i' sound like 'bin' rather than 'bean'.
Regret Intonation
It SHOULD have been done! ↘
Stress on the modal to emphasize the missed obligation.
Deduction Intonation
It MUST have been him. ↗
Rising intonation on the modal to show logical processing.
暗記しよう
記憶術
M.H.B.P: Modals Have Been Perfect (Modal + Have + Been + Participle).
視覚的連想
Imagine a detective (Must) looking at a broken vase (Been Broken) and a crying child (Should Have Been Careful). The detective represents the deduction, the vase is the passive object, and the child represents the regret.
Rhyme
If it should have been done, but the race wasn't won, use 'have been' and the V3 for fun!
Story
A chef forgot the cake in the oven. The kitchen filled with smoke. He thought, 'The timer must have been ignored.' His boss said, 'The cake should have been taken out earlier.' Now, the burnt cake could have been sold, but it's ruined.
Word Web
チャレンジ
Look around your room. Find one thing that is messy or broken. Write one sentence about why it 'should have been fixed' or 'must have been moved'.
文化メモ
British speakers use 'ought to have been' slightly more frequently than Americans in formal contexts to express moral obligation.
Americans heavily favor 'should have been' over 'ought to' and frequently contract it to 'shoulda' in very casual speech.
This structure is used as a 'politeness strategy' to avoid blaming specific employees for mistakes.
The structure evolved from the Old English use of 'sculan' (shall/should) and 'motan' (must) combined with the developing perfect aspect in Middle English.
会話のきっかけ
What is something in history that should have been done differently?
Look at this old photo. What must have been happening when it was taken?
If you could change one thing about your last project, what could have been improved?
Think of a famous mystery. How might the crime have been committed?
日記のテーマ
よくある間違い
Test Yourself
The meeting notes ___ circulated to all attendees yesterday.
Find and fix the mistake:
The critical warning should have give to the team earlier.
Choose the correct sentence:
Arrange the words in the correct order:
All words placed
Click words above to build the sentence
Score: /4
練習問題
8 exercisesThe window was open this morning. It ___ (must / leave) open by the cleaners.
Which of these sentences shows someone is unhappy about a past event?
Find and fix the mistake:
The documents should has been signed yesterday.
Active: Someone must have stolen my bike.
The word 'been' can be omitted in passive perfect modal constructions.
A: Why is the floor so wet? B: I don't know. It ___.
The treasure ___ (might / must / should) have been buried here.
1. Must, 2. Should, 3. Could
Score: /8
Practice Bank
12 exercisesThe new security flaw ___ discovered sooner by the QA team.
Many mistakes might been made if we rushed the launch.
Which sentence is grammatically correct?
Translate into English: 'La decisión debería haber sido tomada hace mucho tiempo.'
Arrange these words into a meaningful sentence:
Match each modal to its corresponding implication in passive perfect form:
The confidential documents ___ accessed without authorization.
Her concerns would have address if she had spoken up earlier.
Which sentence best expresses regret about a past passive event?
Translate into English: 'Él podría haber sido invitado a la fiesta.'
Form a grammatically correct sentence:
Match the sentence beginnings with their appropriate endings:
Score: /12
よくある質問 (8)
No. After a modal verb like `should` or `must`, you always use the base form `have`. Example: `It must have been done.`
They are almost identical in meaning. `Ought to` is slightly more formal and often implies a moral obligation, while `should` is more common in everyday English.
Without `been`, the sentence is active. `The car should have fixed` means the car was trying to fix something. `The car should have been fixed` means someone else was supposed to fix the car.
No. `Will have been done` is the Future Perfect Passive. This rule specifically covers 'modal' verbs like `should`, `could`, and `must` for the past.
Not quite. `Must have been` is a guess (deduction). `Had to be` is a past requirement. `He must have been tired` (I think he was). `He had to be tired` (It was a requirement for the role).
Move the modal to the start: `Should the meeting have been cancelled?`
Usually, `could` and `might` are similar, but `could` often implies a lost opportunity, while `might` is a pure guess about possibility.
Yes! It's great for talking about improvements: `The process could have been streamlined.` It shows you have an analytical mind.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
Debería haber sido + participio
Spanish modals conjugate for person, whereas English modals are invariant.
Aurait dû être + participe passé
French requires agreement in gender and number for the past participle in passive forms.
Hätte ... gemacht werden sollen
The word order is drastically different, with the modal often coming last.
〜されるべきだった (sareru beki datta)
Japanese does not use an auxiliary like 'have' to indicate the perfect aspect; it uses the past tense of the copula.
كان يجب أن يتم (kana yajibu an yutamma)
Arabic lacks a direct 'modal' category like English; it uses verbs of necessity.
应该已经被... (yīnggāi yǐjīng bèi...)
Chinese verbs do not change form (no past participle), relying on particles for time.
Learning Path
Prerequisites
Learn These First
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### Overview 英語学習において、中級から上級（C1レベル）へとステップアップする際、避けて通れないのが「情報の伝え方」の洗...
受動態：行動に焦点を当てる（現在形受動態）
### Overview みなさん、こんにちは。英語学習を進める中で、「受動態（Passive Voice）」という言葉を一度は耳にしたことがあ...
