Grammar Rule in 30 Seconds
Use 'should' to give friendly advice or say what is a good idea without being too bossy.
- Use 'should' + base verb (no 'to'): 'You should go' (not 'should to go').
- Never add 's' for he/she/it: 'She should study' (not 'shoulds').
- Use 'shouldn't' for negative advice: 'You shouldn't smoke.'
Overview
should は、助動詞（modal auxiliary verb）と呼ばれる動詞の一種で、主に「～すべきだ」「～した方が良い」といったアドバイスや提案、あるいは「～のはずだ」という期待や推量を表すために使われます。これは、英語の文法において非常に頻繁に使われる表現であり、特に相手に何かを勧めたり、意見を述べたりする際に、丁寧で自然なニュアンスを伝えるのに役立ちます。must のような強い義務や必要性を表すのではなく、あくまで「～するのが良いだろう」という、相手の選択肢を尊重する柔らかい表現です。主語が誰であっても形が変わらないため、比較的習得しやすい助動詞ですが、その意味合いの多様性を理解することが、より自然な英語表現への鍵となります。should は助動詞（modal verb）であり、いくつかの特徴的な文法規則に従います。助動詞は、主語の人称（I, you, he, she など）や数（単数・複数）によって形が変化しないという性質を持っています。例えば、「shoulds」や「shoulding」といった形は存在しません。また、should の後には、必ず動詞の原形（base form）、つまり to を付けない不定詞（bare infinitive）が続きます。これは、should が主動詞の意味を補強する役割を持つためです。You should to go ではなく、You should go となります。動詞の go は原形のままです。これは、should に限らず、can, will, may などの助動詞に共通するルールです。これらの助動詞は、文の「ムード（mood）」や話し手の「態度（attitude）」を表し、可能、必要、許可、そして should の場合は「妥当性」や「推奨」といった意味合いを、主動詞に付け加えます。この構造の安定性を理解することが、should を正確に使いこなすための第一歩となります。should は否定文や疑問文を作る際に、do のような助動詞を必要としません。これは、通常の動詞（例: I play → Do you play?）とは異なる、助動詞特有の性質です。- 肯定文:
I should go. - 否定文:
I should not go.(またはI shouldn't go.) - 疑問文:
Should I go?
should は文法的に非常に規則的で、その後の動詞の形も一定であるため、学習者はパターンを覚えれば比較的容易に使いこなすことができます。should を使った文の作り方は、主語が何であっても常に同じパターンに従うため、非常に覚えやすいです。以下に、肯定文、否定文、疑問文の基本的な形を示します。should | 動詞の原形 (Base Verb) | 補語・目的語 (Complement/Object) |should | start | earlier. |should | check | your email. |should | exercise | more often. |should | consider | the offer. |should | work | better now. |should | arrive | on time. |should | listen | to the advice. |You should always double-check your work.（あなたは常に仕事を見直すべきです。）She should try that new restaurant; it’s excellent.（彼女はその新しいレストランを試すべきです。とても美味しいですよ。）We should leave soon to avoid the traffic.（渋滞を避けるために、すぐにここを出発すべきです。）
should not は shouldn't と短縮されることが一般的です。should not (shouldn't) | 動詞の原形 (Base Verb) | 補語・目的語 (Complement/Object) |should not | delay. | |shouldn't | worry | too much. |should not | ignore | the warning. |shouldn't | forget | her passport. |should not | happen | again. |shouldn't | make | a hasty decision. |should not | speak | loudly. |You shouldn't stay up late studying for the exam.（試験のために夜遅くまで勉強すべきではありません。）He shouldn't skip meals; it's unhealthy.（彼は食事を抜くべきではありません。体に悪いです。）They should not believe everything they read online.（彼らはオンラインで読むものをすべて信じるべきではありません。）
should が主語の前に置かれます。Should | 主語 (Subject) | 動詞の原形 (Base Verb) | 補語・目的語 (Complement/Object)? |Should | I | call | her? |Should | you | tell | the truth? |Should | he | wait | for them? |Should | she | apologize? | |Should | it | be | done this way? |Should | we | book | tickets in advance? |Should | they | come | with us? |Should I wear a formal suit for the interview?（面接にはフォーマルなスーツを着るべきでしょうか？）Should we inform our manager about this issue?（この問題についてマネージャーに知らせるべきでしょうか？）Should he try to negotiate the price?（彼は値段交渉を試みるべきでしょうか？）
What, Where, When, Why, How などの疑問詞を文頭に置き、特定の情報や具体的なアドバイスを求める場合に使います。should | 主語 (Subject) | 動詞の原形 (Base Verb) | 補語・目的語 (Complement/Object)? |What | should | I | do | next? |Where | should | we | meet? | |When | should | he | submit | the report? |Why | should | she | attend | the workshop? |How | should | they | prepare | for the presentation? |What should I pack for the trip to Berlin?（ベルリン旅行には何を持っていくべきですか？）Where should we go for dinner tonight?（今夜、夕食にどこへ行くべきですか？）How should you respond to this sensitive email?（このデリケートなメールには、どのように返信すべきですか？）
should は非常に多用途な助動詞であり、様々な状況で「妥当性」「義務」「期待」といった意味合いを表すために使われます。以下に、主な使用場面を例文と共に解説します。should の最も一般的な使い方です。ある行動が「賢明である」「有益である」「良い考えである」ことを示唆します。相手に直接的な命令をするのではなく、あくまで「～したらどうですか？」という形で、相手の選択を尊重しながら提案する、より丁寧な方法です。You should really try to get more sleep; it helps with concentration.
If you want to improve your English, you should practice speaking daily.
For better performance, athletes should focus on a balanced diet.
You should visit the new exhibition at the museum; it's fascinating.
I think you should consider applying for that scholarship; your grades are excellent.
should は、一般的に「期待されること」「道徳的に正しいこと」、あるいは「軽い義務」を示すこともあります。これは、must や have to のような強い必要性や義務とは異なり、法的な規則や厳格なルールというよりは、倫理的、習慣的な責任を示唆します。Students should complete their assignments by the deadline to ensure timely feedback.
We should always treat others with respect, regardless of their background.
Drivers should adhere to speed limits for their safety and the safety of others.
should は「～しそうである」「～であると予想される」という意味で、現在の情報、通常の状況、または計画に基づいた「もっともらしい予測」を表します。The package should arrive by Friday, according to the tracking information.
Given his experience, he should be able to solve this problem quickly.
The presentation should start in five minutes; everyone is already seated.
should have + 過去分詞)I should have studied harder for the final exam; I regret my lower grade.
You shouldn't have yelled at your colleague; it was unprofessional.
They should have left earlier to catch their flight, but they got delayed.
should は、第1条件文（If + 現在形, 主節に should）の主節で、特定の条件に対するアドバイスを提供するためによく使われます。ある行動を取った場合に推奨される結果を示します。If you want to improve your vocabulary, you should read more English books.
If she asks for help, you should offer your assistance immediately.
If you experience any technical issues, you should contact our support team.
should は「要求される」「強く推奨される」ことを示すために使われ、ought to と同様に指示的な役割を果たすことがあります。これは、日常的なアドバイスよりも、より規定的な意味合いを持ちます。All employees should familiarize themselves with the company's cybersecurity policy.
Applicants should submit all required documentation by the specified deadline.
For safety reasons, laboratory personnel should wear protective eyewear at all times.
should を使う際に陥りやすい、いくつかの間違いがあります。これらのパターンを認識し、その理由を理解することで、より正確な英語表現ができるようになります。Should の後に to を付けてしまうshould を含む）の後には、動詞の原形（bare infinitive）が直接続きます。to を付けるのは文法的に誤りであり、助動詞の構造を壊してしまいます。- 誤り:
You should to study for your test. - 正しい:
You should study for your test. - 誤り:
She shouldn't to worry about small details. - 正しい:
She shouldn't worry about small details.
to を必要としません。Should と Must / Have to の混同should、must、have to の義務の度合いの違いを区別することは非常に重要です。should はアドバイスや軽い義務を表しますが、must や have to は強い必要性、規則、または外部からの強制を示します。should | must | have to (must とほぼ同義) |You should eat more vegetables. (良い考え) | You must wear a seatbelt. (法的義務) | I have to work late tonight. (外部からの約束) |- 誤り:
You must try that new coffee shop!（これは命令のように聞こえ、親しい友人への勧めとしては不自然です。） - 正しい:
You should try that new coffee shop; their latte is excellent.（「あの新しいカフェ、試してみるといいよ。ラテが素晴らしいんだ。」という、親しい推薦になります。） - 誤り:
He should pay his taxes.（これは事実ですが、法的な義務に対してshouldを使うと、その義務の強さが弱まります。） - 正しい:
He must pay his taxes.またはHe has to pay his taxes.（税金を払うことは法的な義務であり、mustやhave toがより適切です。）
must や have to ほどではありません。学習者は、この日本語の感覚で should を使うことがありますが、これは不適切です。例えば、会議に遅刻しそうな同僚に対して「早く行かなければならないよ」と伝えたい場合、You should go quickly. と言うと、「行った方が良いよ」という軽いアドバイスに聞こえてしまい、緊急性が伝わりません。このような場合は、You must hurry. や You have to hurry. のように、より強い表現を使う必要があります。should は、その中でも特に「アドバイス」「推奨」「軽い義務」に特化しているため、日本語の「～しなければならない」の全てのニュアンスをカバーできるわけではありません。should have + 過去分詞) の誤用should have + 過去分詞 の形は、非常に便利ですが、現在形との混同や、過去分詞の形を間違えることがあります。- 誤り:
I should had studied harder.（hadが重複しています。） - 正しい:
I should have studied harder. - 誤り:
She should went earlier.（wentは過去形であり、過去分詞ではありません。） - 正しい:
She should have gone earlier.
should have は助動詞 should と完了の have から成る複合的な構造であり、その後に続くのは常に過去分詞です。この構造を一つの動詞句として捉えることが重要です。should は、似たような意味合いを持つ他の表現と区別して理解することが重要です。特に、義務や推奨を表す must, have to, ought to との比較は、そのニュアンスの違いを明確にするのに役立ちます。should | アドバイス、推奨、軽い義務、期待 | 弱い | ある |ought to | アドバイス、推奨、道徳的義務（should と似る） | やや弱い | ある |must | 強い義務、必要性、確信 | 強い | ほとんどない |have to | 強い義務、必要性（外部要因によることが多い） | 強い | ほとんどない |need to | 必要性 | 中程度 | ある（必要性が満たされれば不要になる） |Should vs Ought toought to は should と非常に似ており、多くの場合で置き換え可能です。特に道徳的な義務や、よりフォーマルな文脈で使われる傾向があります。しかし、should の方が一般的で、より広い範囲で使われます。You should be kind to your parents.You ought to be kind to your parents.
ought to は少しだけフォーマルで、道徳的な響きが強いかもしれません。）Should vs Must / Have tomust と have to は、法的な義務、規則、または避けられない必要性を表します。一方、should はあくまで「～するのが良い」「～するのが賢明だ」というアドバイスや推奨です。You must stop at a red light.（赤信号では止まらなければならない。→ 法律です。）You should stop and rest if you feel tired.（疲れたら止まって休むべきだ。→ アドバイスです。）
Should vs Need toneed to は、ある行動が必要であることを示しますが、これは義務というよりは、目的を達成するための「必要性」を表します。You should drink water when you are thirsty.（喉が渇いたら水を飲むべきだ。→ アドバイス。）You need to drink water to stay hydrated.（水分補給を続けるためには、水を飲む必要がある。→ 必要性。）
Should は過去形としても使えますか？should 自体は過去形ではありません。should は現在形または未来に対する助動詞です。過去の出来事について話したい場合は、should have + 過去分詞 の形を使います。例えば、「昨日、もっと早く寝るべきだった」は I should have gone to bed earlier yesterday. となります。Should と Could の違いは何ですか？Should はアドバイスや軽い義務を表しますが、Could は可能性、能力、あるいは丁寧な依頼や提案を表します。例えば、「Should I call him?」は「彼に電話すべきでしょうか？」とアドバイスを求めていますが、「Could I call him?」は「彼に電話しても良いですか？」という許可を求めたり、「You could try calling him.」は「彼に電話してみることもできますよ」と可能性や選択肢を提示したりします。Should は疑問詞（What, Whereなど）と一緒に使えますか？What should I do?（何をすべきですか？）のように、疑問詞の後ろに should を置き、その後に主語、動詞の原形と続けます。これは、具体的なアドバイスや指示を求める際に非常に役立つ表現です。Should は must とどのように使い分ければ良いですか？must は、法律、規則、または話し手の強い確信に基づく絶対的な義務や必要性を表します。例えば、「パスポートなしでは入国できません」は You must not enter without a passport. となります。一方、should は、より柔らかいアドバイスや推奨、期待を表します。「健康のために、毎日運動すべきだ」は You should exercise every day. となります。つまり、強制力があるかないかで判断すると分かりやすいでしょう。Conjugation of 'Should'
| Subject | Modal | Base Verb | Example |
|---|---|---|---|
|
I
|
should
|
work
|
I should work.
|
|
You
|
should
|
work
|
You should work.
|
|
He/She/It
|
should
|
work
|
She should work.
|
|
We
|
should
|
work
|
We should work.
|
|
They
|
should
|
work
|
They should work.
|
Contractions
| Full Form | Contraction | Usage |
|---|---|---|
|
should not
|
shouldn't
|
Standard negative
|
|
should have
|
should've
|
Spoken past form
|
|
should not have
|
shouldn't've
|
Very casual spoken
|
Meanings
A modal verb used to express that something is a good idea, a duty, or a likely outcome.
Giving Advice
Suggesting what is the right or best thing to do in a specific situation.
“You should wear a coat; it's freezing outside.”
“I think you should talk to your boss about the problem.”
Logical Probability
Expressing that something is expected to happen based on current facts.
“They left an hour ago, so they should be here soon.”
“The price should be around fifty dollars.”
Regret (Past)
Using 'should have' to express that a past action was a mistake.
“I should have studied harder for the exam.”
“You shouldn't have said that to her.”
Reference Table
| 主語 | Should/Shouldn't | 動詞の原形 | 例 |
|---|---|---|---|
|
I
|
should
|
go
|
I `should go` home now.
|
|
You
|
shouldn't
|
worry
|
You `shouldn't worry` about that.
|
|
He
|
should
|
eat
|
He `should eat` more vegetables.
|
|
She
|
shouldn't
|
be
|
She `shouldn't be` late for the meeting.
|
|
We
|
should
|
try
|
We `should try` that new restaurant.
|
|
They
|
shouldn't
|
forget
|
They `shouldn't forget` their tickets.
|
|
It
|
should
|
work
|
It `should work` after the update.
|
フォーマル度スペクトル
It is recommended that you consult a physician. (Medical advice)
You should see a doctor. (Medical advice)
You ought to get that checked out. (Medical advice)
Man, you gotta see a doc. (Medical advice)
Should：アドバイスとおすすめ
構造
- Subject + should + Base Verb 形成
- shouldn't 否定形
- Should + Subject + Base Verb? 疑問形
用途
- Advice 役立つヒントを与える
- Recommendation 良いことを提案する
- Mild Obligation 期待されること
- Probability 起こりそうなこと
よくある間違い
- should to do 不適切な不定詞
- should does 不適切な活用
- must vs should 義務の強さ
Should と Must の比較
アドバイスのための「Should」の使いどころ
優しい提案やおすすめをしたいですか？
良いアイデアや期待されることを表現していますか？
強い義務、規則、または必要性ですか？
「Should」を使う日常的な状況
友達と社会
- • What should I wear?
- • You should try this game.
- • We shouldn't be late.
仕事と勉強
- • I should finish this report.
- • You should review your notes.
- • We should collaborate more.
健康とライフスタイル
- • You should drink water.
- • I shouldn't eat too much sugar.
- • He should exercise regularly.
旅行と計画
- • We should book flights soon.
- • You should pack light.
- • They shouldn't forget their passport.
レベル別の例文
You should sleep now.
You should sleep now.
I should go home.
I should go home.
Should I eat this?
Should I eat this?
He should drink water.
He should drink water.
You shouldn't walk alone at night.
You shouldn't walk alone at night.
She should study for the test.
She should study for the test.
What should we do today?
What should we do today?
I think you should buy the red car.
I think you should buy the red car.
The package should arrive by Monday.
The package should arrive by Monday.
You should have told me you were coming.
You should have told me you were coming.
If you feel sick, you should see a doctor.
If you feel sick, you should see a doctor.
We should be able to finish this by noon.
We should be able to finish this by noon.
It's only natural that you should feel nervous.
It's only natural that you should feel nervous.
You shouldn't have been driving so fast.
You shouldn't have been driving so fast.
Should the weather improve, we'll go for a hike.
Should the weather improve, we'll go for a hike.
I suggested that he should take a break.
I suggested that he should take a break.
It is vital that every student should attend.
It is vital that every student should attend.
Why should I be the one to apologize?
Why should I be the one to apologize?
The results should, in theory, be consistent.
The results should, in theory, be consistent.
Should you require further assistance, please contact us.
Should you require further assistance, please contact us.
It is quite extraordinary that he should have succeeded.
It is quite extraordinary that he should have succeeded.
That he should think so poorly of us is distressing.
That he should think so poorly of us is distressing.
Lest anyone should forget, the deadline is tomorrow.
Lest anyone should forget, the deadline is tomorrow.
I was shocked that such a thing should happen in this day and age.
I was shocked that such a thing should happen in this day and age.
間違えやすい
They mean the same thing, but 'ought to' is formal and uses 'to'.
Learners use 'must' for advice, which sounds like a command.
Learners don't realize 'had better' is a warning.
よくある間違い
I should to go.
I should go.
He shoulds eat.
He should eat.
I don't should go.
I shouldn't go.
Should I to call?
Should I call?
You must try the cake.
You should try the cake.
I shoulded study.
I should have studied.
You should not to smoke.
You shouldn't smoke.
He should have go.
He should have gone.
I think you shouldn't go.
I don't think you should go.
The bus should to be here.
The bus should be here.
If you should to see him...
Should you see him...
文型パターン
I think you should ___.
Should I ___ or ___?
You shouldn't have ___.
It should be ___ by ___.
Real World Usage
U should totally come tonight!
I believe we should prioritize customer satisfaction.
You should take this medicine twice a day.
Should I get the fries or the salad?
Everyone should watch this video right now! 😂
You should get off at the next stop.
優しく伝えましょう
should try this new recipe.」「should to」は避けて！
should go home.」過去のアドバイスや後悔
should have + 過去分詞」を使います。例えば、「I should have studied more.」のように、後悔を表すのにぴったりです。文化的なニュアンス
should consider his feelings.」短縮形はクール
shouldn't worry.」「should」の使いすぎに注意
take a break?」Smart Tips
Use 'I don't think you should' instead of 'I think you shouldn't'.
Use 'Maybe' or 'Perhaps' before 'should' to be extra polite.
Check if it's a formal 'if' clause.
Contract it to 'should've' in speech, but never write 'should of'.
発音
The Silent 'L'
The 'l' in 'should' is never pronounced. It sounds like 'shood'.
The Contraction 'Shouldn't'
The 't' is often very soft or silent in fast speech.
Rising on 'Should' for questions
Should we GO? ↗
Conveys a genuine request for a suggestion.
暗記しよう
記憶術
Should is for 'Sugar' — it makes advice sweet and easy to swallow.
視覚的連想
Imagine a friendly traffic warden who suggests you park elsewhere instead of giving you a ticket. He is the 'Should' warden.
Rhyme
If you want to be a friend, 'should' is the word you send.
Story
A traveler is lost in London. He sees a sign that says 'You must stop' (Law). He asks a lady for help, and she says 'You should take the Tube' (Advice). He gets on the train and thinks 'It should be 5 minutes' (Expectation).
Word Web
チャレンジ
Write down three things you should do tomorrow to have a productive day.
文化メモ
British speakers often use 'should' where Americans might use 'would' in hypothetical situations, like 'I should think so.'
Americans use 'should' heavily for advice, but 'ought to' is becoming increasingly rare in spoken conversation.
Using 'I think you should' is a standard way to give feedback to a superior without sounding disrespectful.
Derived from the Old English 'sceolde', the past tense of 'sculan' (shall).
会話のきっかけ
I want to learn a new language. Which one should I choose?
I'm bored this weekend. What should I do in this city?
If you could go back in time, what is one thing you should have done differently?
Should the government provide free internet for everyone?
日記のテーマ
よくある間違い
Test Yourself
You ___ remember to save your work frequently.
Find and fix the mistake:
They should to call before visiting.
Choose the correct sentence:
study）が続きます。「studies」ではありません。「must to」は間違いです。「must」の後には「to」はつけません。Arrange the words in the correct order:
All words placed
Click words above to build the sentence
should not + 動詞の原形 + 文の残り」です。Score: /4
練習問題
8 exercisesIt's raining. You ___ take an umbrella.
Find and fix the mistake:
He shoulds call his mother.
Which sentence is correct?
I didn't study, and I failed. (I / study)
You can use 'should' to talk about things you expect to happen.
A: I'm so tired. B: You ___ stay up so late watching TV.
'The movie should be over by 9 PM.'
I have a toothache.
Score: /8
Practice Bank
12 exercisesIf you want to improve, you ___ practice daily.
He shouldn't forgets his keys again.
Which sentence is correct?
Translate into English: 'You should listen carefully.'
Arrange these words into a sentence:
Match the sentence beginnings with their advice endings:
It's late, so you ___ probably go to bed.
We should have goes to the party.
Translate into English: 'What should we do?'
Arrange these words into a question:
Choose the correct sentence:
Match the advice with where you might hear it:
Score: /12
よくある質問 (8)
They mean the same thing, but `ought to` is more formal and requires 'to'. `Should` is much more common in daily speech.
Yes! You can say 'We should go tomorrow.' It functions as a suggestion for a future action.
Because `should` is a modal verb. Modal verbs are special and never change their ending, no matter the subject.
In very formal academic writing, it is better to use `should not`. However, in business emails, `shouldn't` is perfectly fine.
Use the question form: `What should I do?` or `Do you think I should...?`
It expresses regret about the past. `I should have studied` means I didn't study, and now I'm sorry about it.
Yes, in very formal English. `Should you need help...` means `If you need help...`
Yes. `Should` implies it is a good idea or likely, while `might` only implies it is possible.
Scaffolded Practice
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Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
debería
Spanish conjugates for every person (debería, deberías, etc.), while English 'should' never changes.
devrais
French requires the full conjugation and often uses 'tu devrais' vs 'vous devriez' for politeness.
sollte
German word order changes in subordinate clauses, whereas English 'should' stays with the verb.
〜べき (~beki)
Japanese often uses 'hou ga ii' (it would be better) for soft advice where English uses 'should'.
يجب أن (yajib an)
Arabic doesn't have a dedicated word that only means 'should' (advice); context determines the strength.
应该 (yīnggāi)
Chinese doesn't have tenses, so 'should have' requires adding 'le' or other time markers.
Learning Path
Prerequisites
Continue With
助言のための第一条件文 (should)
グループチャットの画面を見つめて、親友にどうアドバイスしようか悩んだことない？ 「偉そうな親」みたいにはなりたくないしね...
Should Have + 過去分詞 (後悔について話す)
Netflixを夜遅くまで見すぎて、飛行機に乗り遅れたことはありませんか？あるいは、親友に送るはずのメッセージを上司に送ってし...
Ought To: 助言と義務
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Should Have: 過去の後悔と間違い
### Overview 過去を振り返って、今の知識で当時の状況を評価する場面は誰にでもありますね。英語でそのような「過去の評価」や...
関連動画
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ゼロ条件法: 習慣と日課
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混合仮定法：過去の行動、現在の結果 (Type 2)
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Suppose & Supposing: もしものゲーム
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