MODALS IN THE PAST FORM

 Modal verbs are special verbs which behave very differently from normal verbs.

Past modals come in two forms. The first type is the easiest and usually requires only a simple word change:

I can drive.I could drive when I was 16. I have to go to California. I had to go to California. Lenny will pay tomorrow. Lenny said he would pay tomorrow.

(present ability)(past ability) (present obligation) (past obligation) (future intention) (future reported from the past

Must / Might / Could / May / Can't + Have + Past Participle

• must have + past participle
• might / might not have + past participle
• could / couldn’t have + past participle
• may / may not have + past participle
• can’t have + past participle

For example :

Question : Where was Julie last night?

1. Answer : She must have forgotten about our date.
2. Answer : She might have worked late.
3. Answer : She could have taken the wrong bus.
4. Answer : She may have felt ill.
5. Answer : She can’t have stayed at home.

Will / Won’t + Have + Past Participle 

Will and won't / will not + have + past participle are used for past certainty ( compare with present use of 'will' above ) : The parcel will have arrived before now.

Should + Have + Past Participle

Should + have + past participle can be used to make an assumption about something that has probably happened, if everything is as we expect (compare with present sue of 'should' above) : The train should have left by now.

Could

We can use could to talk about a general possibility in the past (compare with the use of 'can' above) : Prices could be high in the sixteenth century.

This is not used to talk about specific possibilites in the past: He could have been working late (not: 'could be', which is present)

Past modals with have

Some past modals can be formed by using have + the past participle of the main verb immediately after the modal. (should have, could have, would have, etc.)

However, since modals express possibility, intention, obligation, etc., they do not always indicate a definite tense. Therefore, when using past modals with have, special meanings need to be considered.

I should go to the funeral.I should have gone to the funeral. Lex might take Karen to the airport. Lex might have taken Karen to the airport. Lex could have taken Karen to the airport. Lex would have taken Karen to the airport. Otis didn't come to work yesterday. He had to take care of his children. His children must have been sick.

(I feel an obligation to go--later.)(I didn't go. Now I regret it.) (It's a future possibility.) (He may be on his way there now.) (Most likely he didn't.) (He didn't. He had an excuse.) (past fact) (past obligation) (conjecture about the past) Learn more Modal in the Past