1) Could have
Could have equals pouvoir in the conditional perfect.
| He could have been right. | Il aurait pu avoir raison. | |
| I could have driven there. | J’aurais pu y conduire. |
2) May have
3) Might have
May have and might have = peut-être with a past tense or il se peut + past subjunctive.
| I may / might have left too early. | Je suis parti trop tôt, peut-être. Il se peut que je sois parti trop tôt. |
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| She may / might have been right. | Elle avait peut-être raison. Il se peut qu’elle ait eu raison. |
4) Must have
Must have is equivalent to devoir in the passé composé.
| He must have forgotten. | Il a dû oublier. | |
| I must have tripped. | J’ai dû trébucher. |
5) Shall have
6) Will have
Shall have and will have plus a past participle are both equivalent to the French future perfect.
| We shall have overcome! | Nous aurons vaincu ! | |
| I’ll have left by 2pm. | Je serai parti avant 14h. |
7) Should have
Should have is equivalent to devoir in the conditional perfect.
| You should have studied more. | Tu aurais dû étudier plus. | |
| We should have tried again. | Nous aurions dû essayer encore une fois. |
8) Would have
Would have equals the French conditional perfect.
| I would have liked to see it. | J’aurais aimé le voir. | |
| You would have gotten sick. | Tu serais tombé malade. |