Grammar Rule in 30 Seconds
Use modal passives to focus on the action's necessity or possibility without needing to mention who is performing it.
- Present/Future: Use 'Modal + be + Past Participle' (e.g., 'It must be finished').
- Past: Use 'Modal + have been + Past Participle' (e.g., 'It should have been done').
- Negative: Place 'not' after the modal (e.g., 'It cannot be changed').
Overview
must や should、can といった助動詞が加わることで、「何がなされるべきか」「何が可能か」「何が予測されるか」といった、話し手の主観的な判断や社会的・論理的な制約を、極めて客観的かつ外交的なトーンで表現できるようになります。You must submit the report.（あなたがレポートを出さなければならない）という直接的な表現よりも、The report must be submitted.（レポートは提出されなければならない）という、行為者ではなく「レポートのステータス」に焦点を当てた表現が好まれる場面が多くあります。この章では、この高度な構造をマスターし、ネイティブスピーカーのような洗練された視点を手に入れるための道筋を示します。be + past participle ですが、助動詞が前に来ることで、この be は主語が単数であっても複数であっても、あるいは時制がどうであっても、常に原形の be のまま固定されます。これは日本語の「される」「された」「されれば」といった複雑な活用に比べればシンプルですが、英語特有の「語順による役割決定」を強く意識する必要があります。by ... で後付け、または省略 | そもそも主語を省略することが多い |be を抜かしてしまったり、過去分詞の形を間違えたりすることがあります。パターンを身体に染み込ませることが重要です。Subject + Modal Verb + be + Past Participle (V3)- 肯定文:
The task can be completed by tomorrow.（そのタスクは明日までに完了できる。） - 否定文:
The information should not be shared.（その情報は共有されるべきではない。） - 疑問文:
Could the meeting be rescheduled?（会議の日程を変更することは可能でしょうか？）
- 1Must be + V3 (強い義務・論理的確信):
Safety goggles must be worn at all times.（保護メガネは常に着用しなければならない。）The error must be corrected immediately.（そのエラーは直ちに修正されなければならない。）
- 1Should be + V3 (義務・推奨・当然の期待):
The feedback should be taken seriously.（そのフィードバックは真剣に受け止められるべきだ。）The results should be announced soon.（結果はまもなく発表されるはずだ。）
- 1Can / Could be + V3 (可能性・能力・許可):
A solution can be found.（解決策は見つかるはずだ。）The problem could be solved with more resources.（より多くのリソースがあれば、問題は解決できるかもしれない。）
- 1May / Might be + V3 (推量・許可):
The flight might be delayed due to the storm.（嵐のためにフライトが遅れるかもしれない。）Permission may be granted upon request.（リクエストに応じて許可が与えられる場合がある。）
- 1Will / Would be + V3 (未来・意志・仮定):
The bridge will be finished next year.（その橋は来年完成する予定だ。）The proposal would be accepted if it were more detailed.（もしもっと詳細であれば、その提案は受け入れられるだろうに。）
The files were lost.(誰が失くしたかは問わず、ファイルがなくなった事実が重要)The contract will be signed tomorrow.(誰がサインするかは既知、あるいは事務的なプロセスなので、契約という事象に焦点を当てる)
You made a mistake. と言うと攻撃的に聞こえますが、受動態を使うことで角を立てずに問題を指摘できます。これは日本語の「敬語」や「遠回しな表現」に近い感覚です。A mistake was made in the calculations.（計算にミスがありました。）The deadline might be missed.（締め切りに間に合わない可能性があります。）
The samples must be kept at zero degrees.（サンプルは0度で保管されなければならない。）It can be argued that...（...という議論が可能である。）
Passwords should be changed every three months.（パスワードは3ヶ月ごとに変更されるべきです。）Applications cannot be accepted after the deadline.（締め切り後の申請は受理できません。）
must be や cannot be を使って、強い確信を伴う推論を表現します。The noise is so loud; it can be heard from the street.（音がとても大きい。通りからでも聞こえるほどだ。）This result could not be achieved without your help.（あなたの助けがなければ、この結果は達成できなかったでしょう。）
be の脱落 (The Missing be)must の後に直接過去分詞を置いてしまうミスが多発します。- Incorrect:
The report must finished by 5 PM. - Correct:
The report must be finished by 5 PM. - なぜ間違えるのか: 日本語の「終わらされる」という感覚を
finishedだけで表現できると錯覚してしまうためです。助動詞の後は必ず「動詞の原形」が必要であり、受動態を作るためにはbeが不可欠であることを再認識しましょう。
be の活用ミス (Incorrect Inflection)be を is や are に変えてしまうミスです。- Incorrect:
The documents can are sent electronically. - Correct:
The documents can be sent electronically. - なぜ間違えるのか:
The documents are sentという通常の受動態の形が頭に強く残っているため、助動詞が入ってもその形を維持しようとしてしまうからです。助動詞は「強力な磁石」のようなもので、後ろの動詞を強制的に原形（be）に引き戻すとイメージしてください。
- Incorrect:
The decision should be took soon. - Correct:
The decision should be taken soon. - なぜ間違えるのか: 過去形
tookと過去分詞takenの区別が曖昧なまま、なんとなく「過去っぽい形」を選んでしまうためです。C1レベルでは、不規則動詞のV3形を完璧に使いこなすことが信頼に繋がります。
I must be helped by him. と言うと、「彼に助けられなければならない（強制的な受動）」という不自然な響きになります。日本語の「〜してもらう」は恩恵を表しますが、英語の受動態は単なる構造的な焦点移動です。恩恵を表したい場合は I need him to help me. や I should have him help me. の方が自然です。We should finish the project. | 私たちがやる、という責任感と主体性が強い。 |The project should be finished. | プロジェクトの完了という「結果」に焦点。誰がやるかは二次的。 |I must have the car repaired. | 専門家や他人に依頼して「〜してもらう」という使役のニュアンス。 |It is necessary to finish the project. | 客観的な必要性を述べるが、受動態ほど簡潔ではない。 |Should be done vs Ought to be doneought to be done の方が「道徳的な義務」や「社会的な正当性」をより強く含みます。ビジネスの契約や規則では should be が一般的ですが、倫理的な議論では ought to be が選ばれることがあります。Can be done vs Is able to be doneable to は受動態で使われることは稀です。能力を表す be able to は通常「人」を主語にするため、物を主語にする受動態では can be done や is possible to be done（あるいは単に is possible）が好まれます。by を使って行為者を示すのはどんな時ですか？The law was signed by the President himself.（その法律は大統領自らによって署名された）のように、誰が行ったかがニュース価値を持つ場合にのみ by を使います。それ以外（誰がやったか明白な場合など）は、省略するのが「洗練された英語」です。get を使った受動態 (can get done) との違いは？get を使った受動態はより口語的で、カジュアルな響きになります。The work can get done. は「なんとか終わらせられるよ」という少し砕けた、あるいは「困難を乗り越えて」というニュアンスが含まれます。公式な文書やプレゼンテーションでは、常に be を使うべきです。must have been done と言えますか？The window must have been broken from the outside.（窓は外から割られたに違いない）のように使います。これは C1 レベルで必須の「助動詞＋完了受動態」というさらに高度な形です。Close the door.（ドアを閉めろ）よりも、The door should be kept closed.（ドアは閉めておくべきです）の方が、相手に対する直接的な命令ではなく「あるべき状態」を示唆するため、プロフェッショナルな環境では好まれます。日本語の「〜していただければと思います」というニュアンスに近いソフトな響きになります。Modal Passive Formation
| Timeframe | Modal | Auxiliary | Verb Form | Example |
|---|---|---|---|---|
|
Present/Future
|
can/must/should
|
be
|
Past Participle (V3)
|
It can be done.
|
|
Past
|
could/should/must
|
have been
|
Past Participle (V3)
|
It should have been done.
|
|
Negative (Pres)
|
cannot/must not
|
be
|
Past Participle (V3)
|
It must not be done.
|
|
Negative (Past)
|
might not
|
have been
|
Past Participle (V3)
|
It might not have been done.
|
|
Question
|
Should
|
Subject + be
|
Past Participle (V3)
|
Should it be done?
|
Common Contractions
| Full Form | Contracted Form | Usage Note |
|---|---|---|
|
cannot be
|
can't be
|
Very common in speech
|
|
should not be
|
shouldn't be
|
Common in advice
|
|
must not be
|
mustn't be
|
Common in British English
|
|
should have been
|
should've been
|
Spoken English only
|
Meanings
The modal passive is used to express necessity, possibility, permission, or obligation regarding an action where the receiver of the action is the subject.
Obligation and Necessity
Expressing that an action is required to be performed on an object.
“Safety goggles must be worn at all times in the lab.”
“The taxes should be paid by the end of the month.”
Possibility and Ability
Expressing what can or could happen to an object.
“The problem could be solved with more funding.”
“This software can be downloaded for free.”
Past Regret or Deduction
Reflecting on actions that were or weren't performed in the past.
“The mistake should have been caught during the review.”
“The package must have been delivered to the wrong address.”
Reference Table
| 助動詞 | 意味 | 能動態の例 | 受動態の例 |
|---|---|---|---|
|
can
|
Ability/Possibility
|
They can solve the problem.
|
The problem can be solved.
|
|
could
|
Possibility/Suggestion
|
We could reschedule the meeting.
|
The meeting could be rescheduled.
|
|
may
|
Permission/Possibility
|
You may use this tool.
|
This tool may be used.
|
|
might
|
Slight Possibility
|
She might send the email.
|
The email might be sent.
|
|
must
|
Obligation/Necessity
|
Students must read the book.
|
The book must be read.
|
|
should
|
Advice/Recommendation
|
You should review the report.
|
The report should be reviewed.
|
|
will
|
Future Certainty (passive)
|
They will complete the task.
|
The task will be completed.
|
|
would
|
Hypothetical Outcome
|
Someone would enjoy this.
|
This would be enjoyed.
|
フォーマル度スペクトル
The report must be finalized by the close of business. (Workplace deadline)
The report should be finished soon. (Workplace deadline)
The report's gotta be done. (Workplace deadline)
This doc needs to be wrapped up ASAP. (Workplace deadline)
助動詞と受動態：コアコンセプト
主要要素
- Modal Verb Can, Should, Must, etc.
- be Always 'be'
- Past Participle V3 form
主な目的
- Focus on Action Not the doer
- Agent Unknown Or unimportant
- Politeness Indirect requests/suggestions
使用される文脈
- Instructions Rules, procedures
- Possibilities Future outcomes
- Advice Recommendations
能動態 vs. 助動詞と受動態
助動詞と受動態を使うべきか？
行動の主体は不明または重要ではありませんか？
可能性、必要性、または助言を表現する必要がありますか？
よりフォーマルまたは客観的に聞こえるようにしたいですか？
受動態における助動詞の意味
義務
- • Must be done
- • Has to be done
可能性
- • Can be done
- • Could be done
- • May be done
- • Might be done
助言
- • Should be done
- • Ought to be done
未来
- • Will be done
レベル別の例文
The car can be washed.
El coche se puede lavar.
The food must be eaten.
La comida debe ser comida.
The door should be closed.
La puerta debería estar cerrada.
Can the window be opened?
¿Se puede abrir la ventana?
The bill must be paid now.
La cuenta debe pagarse ahora.
The letters can be sent tomorrow.
Las cartas pueden enviarse mañana.
The room should be cleaned every day.
La habitación debe limpiarse todos los días.
This game cannot be played alone.
Este juego no se puede jugar solo.
The results might be announced later today.
Los resultados podrían anunciarse más tarde hoy.
All staff members must be informed of the change.
Todos los miembros del personal deben ser informados del cambio.
The bridge could be built in two years.
El puente podría construirse en dos años.
Should the meeting be rescheduled?
¿Debería reprogramarse la reunión?
The report should have been submitted yesterday.
El informe debería haber sido entregado ayer.
The software may be updated automatically.
El software puede actualizarse automáticamente.
The suspect must have been seen by someone.
El sospechoso debe haber sido visto por alguien.
These rules ought to be followed strictly.
Estas reglas deberían seguirse estrictamente.
The proposal could have been more clearly articulated.
La propuesta podría haber sido articulada más claramente.
It must be ensured that all safety protocols are met.
Debe asegurarse de que se cumplan todos los protocolos de seguridad.
The data might have been misinterpreted by the researchers.
Los datos podrían haber sido malinterpretados por los investigadores.
Such behavior will not be tolerated in this institution.
Tal comportamiento no será tolerado en esta institución.
The nuances of the contract ought to have been more thoroughly scrutinized.
Los matices del contrato deberían haber sido escrutados más a fondo.
The artifacts may well have been being moved when the fire broke out.
Es muy posible que los artefactos estuvieran siendo trasladados cuando estalló el incendio.
It shall be deemed that the agreement is null and void.
Se considerará que el acuerdo es nulo y sin valor.
The project could not have been brought to fruition without your support.
El proyecto no podría haber llegado a buen término sin su apoyo.
間違えやすい
Learners often use the active form when they mean the passive, especially with 'should have'.
Mixing up the perfect active and perfect passive.
Using 'must not' for logical impossibility.
よくある間違い
It must done.
It must be done.
The car can washed.
The car can be washed.
It can be do.
It can be done.
Must be it done?
Must it be done?
It should be finish.
It should be finished.
The bill must be pay.
The bill must be paid.
It not can be done.
It cannot be done.
It should have done.
It should have been done.
The work might been finished.
The work might have been finished.
It must be being done.
It must be done.
The data should have been being analyzed.
The data should have been analyzed.
It ought to been seen.
It ought to have been seen.
The results can be interpreted as...
The results could be interpreted as...
It must not have been done.
It can't have been done.
文型パターン
The ___ must be ___ by ___.
It could be argued that ___.
The ___ should have been ___ earlier.
Under no circumstances may the ___ be ___.
Real World Usage
The files should be uploaded to the shared folder by EOD.
The deposit shall be returned within 30 days.
The bracket must be secured with four screws.
The results could be interpreted as a shift in consumer behavior.
Baggage must not be left unattended.
Your password can be reset using the link below.
「be」は常に忘れずに！
過去分詞（V3）に注意！
「by」は必要な時だけに
状況が全てを決める
副詞の配置は柔軟に
might be easily understood）。こうすることで、表現にニュアンスと正確さをもたらすことができますよ。「The instructions should be clearly explained.」のように、どこに副詞を入れるかで意味合いが変わります。
Smart Tips
Change 'I must finish this' to 'This must be finished'. It sounds less like a personal struggle and more like a professional requirement.
Use 'should have been' to focus on the task. It reduces conflict.
Check if there is a modal before it. If so, it's a modal passive!
Use 'could be interpreted' or 'might be seen' to avoid sounding too aggressive with your claims.
発音
Reduction of 'be'
In the phrase 'must be done', the word 'be' is often unstressed and shortened.
Contraction of 'have been'
In 'should have been', 'have been' often sounds like 'av-bin' or 'əv bɪn'.
Stress on the Modal
It MUST be done! (Falling arrow on MUST)
Emphasizing the urgency or necessity.
暗記しよう
記憶術
Remember 'MBP': Modal + Be + Participle. It's the 'Most Basic Passive' for modals!
視覚的連想
Imagine a robot (the object) being repaired. The robot doesn't fix itself; it 'must be fixed' by a factory arm. The focus is on the robot, not the arm.
Rhyme
If a modal is what you see, don't forget to add the 'be'!
Story
A detective arrives at a crime scene. He says, 'The safe must have been opened from the inside. The guards should have been alerted.' He focuses on the objects and actions because the criminal is unknown.
Word Web
チャレンジ
Look around your room. Find 3 things that 'should be cleaned' and 2 things that 'could be moved'. Say them out loud.
文化メモ
British speakers use 'mustn't be' more frequently than Americans, who prefer 'can't be' or 'shouldn't be' for prohibitions.
Modal passives are the standard for 'polite distancing'. It allows a manager to criticize a process without criticizing a person.
The modal 'shall' is almost exclusively used in legal passives to indicate a mandatory requirement.
The passive voice in English evolved from Old English 'weorthan' (to become) and 'beon' (to be). Modals were originally full verbs with their own meanings.
会話のきっかけ
What is one thing in your city that should be improved?
Think of a famous historical event. What should have been done differently?
If you were the president, what laws would be changed immediately?
Can a person's character be judged by their clothes?
日記のテーマ
よくある間違い
Test Yourself
The new rules ___ reviewed by the committee soon.
Find and fix the mistake:
The report should be write by tomorrow morning.
Arrange the words in the correct order:
All words placed
Click words above to build the sentence
Score: /3
練習問題
8 exercisesThe report ___ (must / finish) by tomorrow morning.
Find and fix the mistake:
The car should been fixed yesterday.
Which sentence is most objective?
The stars...
In a modal passive, the word 'be' changes to 'am/is/are' depending on the subject.
A: Why is the office so messy? B: I don't know, it ___ (should / clean) last night.
Select the correct form.
Must be done / Could be done / Should have been done
Score: /8
Practice Bank
13 exercisesThe payment ___ processed by the end of the week.
Her application could be approve soon.
Choose the correct sentence:
Translate into English: 'El problema puede ser resuelto.'
Arrange these words into a sentence:
Match the active sentences with their correct passive modal equivalents:
This sensitive information ___ not be shared outside the company.
A decision will being made by next week.
Which sentence is correct?
Translate into English: 'Se podría discutir en la reunión.'
Rearrange these words into a sentence:
Your reservation ___ be confirmed shortly via email.
Match the modal with its implied context:
Score: /13
よくある質問 (8)
Yes, in informal English. For example, 'It needs to get done' instead of 'It needs to be done'. However, 'be' is much more common in writing.
'Must not be' is for rules (prohibition), while 'cannot be' is for things that are impossible.
Use the word `by` at the end. 'The law must be signed `by the President`.'
Yes, they are almost identical in meaning, but 'ought to' is slightly more formal or moralistic.
Technically yes (modal passive continuous), but it is very rare and usually replaced by simpler forms like 'might be happening'.
To sound objective. Scientists care about the experiment, not the person holding the test tube. 'The liquid must be heated' sounds more scientific than 'I must heat the liquid'.
No, you are missing the word `have`. It must be 'It should `have` been done'.
When the 'doer' of the action is the most important part of the sentence or when you want to be very direct and personal.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
Pasiva con estar/ser o Pasiva Refleja
English uses 'be' + V3, while Spanish often uses 'se' + active verb.
Voix passive avec les modaux
French uses 'on' more frequently than English uses the passive.
Passiv mit Modalverben
German puts the past participle and 'werden' at the end of the sentence.
助動詞 + 受動態 (reru/rareru)
Japanese uses verb suffixes rather than auxiliary verbs like 'be'.
المبني للمجهول مع الأفعال الناقصة
Arabic uses internal vowel changes (morphology) rather than a 'be' auxiliary.
被 (bèi) + Modal
Chinese lacks verb conjugation and the 'be' auxiliary for passives.
Learning Path
Prerequisites
Learn These First
Continue With
関連動画
03:39 Rogue One: Darth Vader's Fortress
06:28 Eternals Vs Ikaris - Final Fight Scene | ETERNALS (2021) Sci-Fi, Movie CLIP HD
13:23 What’s really happening in Iran right now
PASSIVE VOICE - English Grammar step-by-step
Arnel's Everyday English
Active and Passive Voice Tricks | Active Voice and Passive Voice in English Grammar | ChetChat
ChetChat
Related Grammar Rules
客観性のための受動態：「～と言われている」
### Overview 英語の文法には、情報源を特定せずに情報を伝えたり、情報を述べた人よりも情報そのものを強調したりするための特...
法助動詞と受動態の報告表現（C1レベル）
### 概要 リポートスピーチ（間接話法）における助動詞の扱い、そして受動態を用いた報告構文の習得は、英語力をC1レベルへと引...
報告動詞：誰が何を言った？
### Overview 英語を学んでいる皆さんは、誰かが言ったことを他人に伝える際、つい `say` や `tell` ばかりを使っていませんか...
受動態を使う時（ニュースや噂を報告する際）
Overview X（Twitter）をスクロールしていて、「新作の GTA が来週発売されるという噂がある（It is rumored that the new GTA...
受動態報告構造（彼は～だと言われている）
### 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...
