助動詞完了: must have / should have
実用的な例で語彙を増やそう
Use 'must have' + past participle to make a confident deduction about the past — when you're almost certain something was true based on evidence: 'She must have left already — her car is gone.'
The structure is fixed: must have + past participle, for all subjects.
例文
She must have left already — her car is gone.
Confident deduction from evidence.
He must have known about it.
must have + past participle.
It must have been very expensive.
Near-certainty about the past.
must have left
/mʌst həv left/
She must have left already — her car is gone.
must have known
/mʌst həv noʊn/
He must have known about it.
must have been
/mʌst həv bɪn/
It must have been very expensive.
Her car is gone. Choose: She ___ left already.
Complete the deduction: It must ___ been very expensive. (have)
Use 'should have' + past participle to talk about the right thing to do that didn't happen — expressing regret or criticism: 'You should have called me.'
The negative 'shouldn't have' criticises something that was done but was a mistake: 'I shouldn't have eaten so much cake.'
例文
You should have called me — I was worried.
Criticism: the right action didn't happen.
I should have told you the truth.
Regret about a past omission.
I shouldn't have eaten so much cake.
Regret about something you did do.
should have called
/ʃʊd həv kɔːld/
You should have called me — I was worried.
should have told
/ʃʊd həv toʊld/
I should have told you the truth.
shouldn't have eaten
/ˈʃʊdənt həv ˈiːtən/
I shouldn't have eaten so much cake.
shouldn't have said
/ˈʃʊdənt həv sed/
He shouldn't have said that — it was rude.
You regret eating too much. Choose: I ___ so much cake.
Criticism: You should ___ called me — I was worried. (have)
Use 'could have' or 'might have' (also 'may have') + past participle to talk about past possibilities — things that were possible but maybe didn't happen: 'She might have forgotten the meeting.'
'Could have' can also describe an unrealised ability: 'I could have helped you, but you didn't ask.'
例文
I could have helped you, but you didn't ask.
Unrealised past ability.
She might have forgotten the meeting.
A past possibility (we're not sure).
He may have left his phone at home.
may have = a possible explanation.
could have helped
/kʊd həv helpt/
I could have helped you, but you didn't ask.
could have been
/kʊd həv bɪn/
It could have been a disaster.
might have forgotten
/maɪt həv fərˈɡɒtən/
She might have forgotten the meeting.
may have left
/meɪ həv left/
He may have left his phone at home.
You're not sure why she missed it. Choose: She ___ the meeting.
Unrealised ability: I could have ___ you, but you didn't ask. (helped)
Use 'can't have' or 'couldn't have' + past participle to say something was impossible — you're certain it did NOT happen: 'You can't have seen her — she's been in Paris all week.'
It's the opposite of 'must have': must have = certainly did; can't have = certainly didn't.
例文
You can't have seen her — she's been in Paris all week.
Certainty that it didn't happen.
He couldn't have done it on his own.
Impossibility in the past.
They can't have finished already — it's too soon.
can't have = logically impossible.
can't have seen
/kɑːnt həv siːn/
You can't have seen her — she's been in Paris all week.
couldn't have done
/ˈkʊdənt həv dʌn/
He couldn't have done it on his own.
She's been away all week. Choose: You ___ seen her.
Past impossibility: He couldn't ___ done it on his own. (have)
次へ
倒置（基礎）