should

should — modal verb

1. use this modal verb to say that someone has a duty or that an action is wise and

1.情態動詞A2
釋義

use this modal verb to say that someone has a duty or that an action is wise and fitting — it also forms questions that seek advice about the best possible steps to take

例句

Quinn should apologize to his sister for breaking her guitar.

should + base verb for obligation

What should I wear to the dinner party tonight?

question form: should + subject + verb

同義詞
  • ought to

    slightly more formal and emphatic than 'should' for moral duty

  • had better

    stronger and more urgent than 'should', often implies a warning

反義詞

文法句型

should + base verb

should + not + base verb

Should + subject + base verb?

用法筆記

Common in both affirmative and negative forms. The negative 'shouldn't' is used to discourage or advise against an action. Questions with 'should' seek judgment about the right course of action.

常見錯誤

❌You should to brush your teeth before bed.
✅You should brush your teeth before bed.
💡'should' is followed by the base form of the verb, not the infinitive with 'to'.

2. expresses that something is likely to be true or is expected to happen, given th

2.情態動詞A2
釋義

expresses that something is likely to be true or is expected to happen, given the facts or circumstances that are known

例句

The train should arrive at platform three in about five minutes.

should + verb for expected event

Élise should be home by now — her class ended over an hour ago.

should + be + adverb for expected state

同義詞
  • ought to

    can also express expectation, but slightly more formal

  • be likely to

    more explicit about probability than 'should'

文法句型

should + base verb

should + be + adjective/noun

should not + verb

should + have + past participle

用法筆記

Frequently used with time expressions (by now, in five minutes, soon) and with 'be' as the main verb. The negative 'should not / shouldn't' expresses that something is not expected. For past expectations that did not happen, use 'should have + past participle' (e.g., 'The train should have arrived by now').

常見錯誤

❌The package should arrives tomorrow.
✅The package should arrive tomorrow.
💡the verb after 'should' stays in its base form regardless of the subject.

3. used in conditional sentences to talk about something that might happen, especia

3.情態動詞B1
釋義

used in conditional sentences to talk about something that might happen, especially when it is not very likely or when you want to sound polite

例句

If you should see Zayd at the conference, please give him this folder.

if + subject + should + verb for unlikely condition

Should it rain tomorrow, the outdoor concert will be moved inside.

inverted conditional: Should + subject + verb

同義詞
  • happen to

    used in the same conditional pattern for even less likelihood: 'If you happen to see him...'

文法句型

if + subject + should + verb

Should + subject + verb (inverted)

if + subject + should + happen to + verb

用法筆記

More formal than a simple 'if' clause. 'Should' can be placed before the subject, removing 'if' entirely — this inversion is common in official documents and formal letters. In everyday speech, a simple present tense in the if-clause is more natural: 'If you see Zayd...'

常見錯誤

❌If you should to see him, tell him I called.
✅If you should see him, tell him I called.
💡'should' is directly followed by the base form, not 'to + verb'.

4. placed after 'that' in clauses that follow words expressing emotions, judgments,

4.情態動詞B1
釋義

placed after 'that' in clauses that follow words expressing emotions, judgments, or reactions — for instance, when saying something seems odd, surprising, or completely normal

例句

It is strange that she should refuse such a generous offer.

It is + adjective + that + subject + should + verb

Femi was surprised that Otis should have forgotten his own birthday.

subject + be + adjective + that + subject + should have + past participle

文法句型

It is + adjective + that + subject + should + verb

subject + be + adjective + that + subject + should + verb

It is + noun + that + subject + should + verb

用法筆記

Primarily used in formal or written English. In informal conversation, speakers often omit 'should' and use a simple present tense instead: 'It's strange that she refuses such a generous offer.' Distinguish from sense 5 (SUGGESTION OR DEMAND), which follows verbs of suggestion rather than adjectives of feeling.

常見錯誤

❌It is odd that she should has left so early.
✅It is odd that she should have left so early.
💡use 'should have + past participle', not 'should has' or 'should had'.

5. used after 'that' in clauses that express a suggestion, arrangement, demand, or

5.情態動詞B1
釋義

used after 'that' in clauses that express a suggestion, arrangement, demand, or important aim — for example, when someone recommends, proposes, or requires something

例句

The committee recommended that the funds should be used for new equipment.

recommend + that + subject + should + verb

It is essential that every passenger should complete the safety form before boarding.

It is + adjective + that + subject + should + verb for necessity

同義詞
  • ought to

    can also express a recommendation, but is less common in this that-clause pattern

文法句型

verb + that + subject + should + verb

It is + adjective + that + subject + should + verb

noun + that + subject + should + verb

用法筆記

In American English, the subjunctive form without 'should' is more common: 'The committee recommended that the funds be used…' Both forms are correct. In British English, 'should' is still frequent in this pattern, though it is becoming less common in informal contexts. Distinguish from sense 4 (THAT-CLAUSE FEELINGS), where the main clause describes a feeling rather than a suggestion or requirement.

常見錯誤

❌The doctor suggested that I should resting for a few days.
✅The doctor suggested that I should rest for a few days.
💡use the base form after 'should', not the -ing form.

6. used after 'so that' or 'in order that' to state the purpose of an action — show

6.情態動詞B1
釋義

used after 'so that' or 'in order that' to state the purpose of an action — showing what someone hopes to achieve by doing something

例句

Tamar left the office early so that she should not miss the last train.

so that + subject + should not + verb for negative purpose

The instructions were written in plain language so that everyone should understand them.

so that + subject + should + verb for positive purpose

文法句型

so that + subject + should + verb

in order that + subject + should + verb

用法筆記

This structure is quite formal. In everyday speech, 'so that' + a present or past tense verb is more natural: 'She left early so that she would not miss the train.' In American English, this construction is very rare; 'can', 'could', 'will', or 'would' are preferred instead of 'should'.

7. used after "in case", "for fear that", or "lest" to describe a bad thing that so

7.情態動詞B2
釋義

used after "in case", "for fear that", or "lest" to describe a bad thing that someone wants to avoid by doing something else first.

例句

Jessica took an umbrella in case it should rain during her walk.

in case + should + rain

The teacher wrote down each step for fear that anyone should get lost.

for fear that + should + get lost

文法句型

in case + subject + should + bare infinitive

for fear that + subject + should + bare infinitive

lest + subject + should + bare infinitive

用法筆記

Lest is very formal and rare in everyday speech. In case and for fear that are more common. American English often uses the present simple or subjunctive instead of should in these patterns (e.g., 'in case it rains' instead of 'in case it should rain').

常見錯誤

❌I took a map lest I get lost.
✅I took a map lest I should get lost.
💡After 'lest', British English typically uses 'should' + verb; the bare subjunctive ('get') is possible but less common.
❌She prepared food for fear that the guests should be hungry.' (correct structure, but unnatural)
✅She prepared food in case the guests got hungry.
💡'for fear that' is quite formal; 'in case' is more natural in everyday contexts.

8. used with "why" in questions where the speaker is asking for a reason, stubbornl

8.情態動詞B2
釋義

used with "why" in questions where the speaker is asking for a reason, stubbornly refusing a request, feeling annoyed, or reacting with surprise or disbelief.

例句

Why should I apologise when I did nothing wrong?

Why should + I + verb — expressing refusal

Kenji asked why anyone should have to wait so long for a simple answer.

同義詞
  • ought to

    Cannot be used in 'why...?' questions ('Why ought I to?') — sounds very unnatural.

文法句型

why + should + subject + bare infinitive

用法筆記

When the speaker wants to refuse a request or show annoyance, 'why should I/we...' carries a strong emotional tone — it implies 'I have no reason or obligation to do this.' Distinguish from sense 1 (CORRECT THING), where 'should' expresses obligation: 'You should go' is quite different from 'Why should I go?'

常見錯誤

❌Why should he comes so early?
✅Why should he come so early?
💡After 'should', always use the bare infinitive, not an -s form.
❌I don't know why should I go.
✅I don't know why I should go.
💡In embedded questions (after 'I don't know why'), do NOT invert subject and 'should'.

9. in formal British English, a variant of "would" reserved for first-person subjec

9.情態動詞B2
釋義

in formal British English, a variant of "would" reserved for first-person subjects ("I" and "we") — found in reported statements, tentative remarks, polite requests, and conditional statements about imaginary situations.

例句

I said I should be home before dinner, but the train was delayed.

reported shall → should in indirect speech

We should be grateful if you could confirm your attendance by Friday.

polite request with I/we should

同義詞
  • would

    Now the standard choice for all persons in most varieties of English; 'should' in this sense sounds formal or old-fashioned.

文法句型

I/we + should + bare infinitive

I/we should have + past participle

if + clause, I/we should + bare infinitive

用法筆記

This use of 'should' for I/we instead of 'would' is much more common in formal British English than in American English, where 'would' is used for all persons. Many British speakers also now use 'would' in everyday speech. Distinguish from sense 1 (CORRECT THING): 'I should go' can mean either 'I ought to go' (sense 1) or 'I would go' (sense 9), depending on context.

常見錯誤

❌He should be happy if you visited him.' (confusing two senses)
✅He would be happy if you visited him.
💡For hypothetical 'would' with he/she/it, use 'would', not 'should'. 'Should' in this sense only works with I/we.
❌I should appreciate if you reply soon.
✅I should appreciate it if you replied soon.
💡The pattern needs an object ('it') and a past-tense verb in the if-clause for the polite request.

10. used in questions and exclamations to express strong surprise, disbelief, or to

10.情態動詞B2
釋義

used in questions and exclamations to express strong surprise, disbelief, or to suggest that something is remarkable or amusing — for example, saying "You should see the view!" to mean the view would amaze whoever saw it.

例句

You should see the size of the cake Yan baked — it was enormous!

You should see... for suggesting amazement

How should I know where Christopher left his phone?

How should + I + know — expressing disbelief

文法句型

why/how + should + subject + verb?

you should see/hear/try...

用法筆記

The pattern 'You should see / hear / try...' is a fixed expression that does NOT give advice — it means 'If you saw/heard/tried it, you would be surprised or impressed.' Distinguish from sense 1 (CORRECT THING), where 'you should see a doctor' means 'it is a good idea for you to see a doctor.'

常見錯誤

❌You should see a doctor — the sunset is beautiful!' (confusing two senses)
✅You should see the sunset
💡it is beautiful!' — When 'should' expresses surprise/amazement, it is followed by the thing that is impressive, not a person.
❌Why should the car suddenly break?' (missing 'down')
✅Why should the car suddenly break down?
💡Keep the phrasal verb intact; 'should' doesn't cancel the particle.

11. used with "I" to give advice or a suggestion to someone in a polite, indirect wa

11.情態動詞B2
釋義

used with "I" to give advice or a suggestion to someone in a polite, indirect way — often followed by "if I were you" to soften the recommendation.

例句

I should book the tickets this week if I were you — prices will go up.

I should... if I were you for polite advice

If I were you, I should check the weather before planning the barbecue.

同義詞
  • ought to

    Cannot replace 'I should... if I were you' because 'I ought to... if I were you' sounds unnatural.

  • would

    'I would... if I were you' is now the more common form in both British and American English; 'I should' is slightly more formal or old-fashioned.

文法句型

I should + bare infinitive

I should + bare infinitive + if I were you

if I were you, I should + bare infinitive

用法筆記

This sense is nearly always used with 'if I were you' or in a context where the listener knows the speaker is giving indirect advice. It sounds polite and friendly, not pushy. Distinguish from sense 1 (CORRECT THING): 'You should go' (direct advice, sense 1) vs 'I should go if I were you' (indirect, polite, sense 11). The grammar is different — sense 11 always starts with 'I', while sense 1 can have any subject.

常見錯誤

❌You should talk to her if I were you.
✅I should talk to her if I were you.
💡The 'if I were you' pattern only works with 'I should', not 'you should'.
❌I should you call the doctor.
✅I should call the doctor if I were you.
💡After 'I should', the main verb comes directly; there is no object between 'should' and the verb.