Should / ought to / must have + past participle

Should (Ought to) Have

Should have + past participle is used to indicate past events which did not happen, and describes a mistake or regret over it.


For Example:

You should (ought to) have checked your report thoroughly before you handed it in.

You should (ought to) have asked my permission before you used my computer. I’m really angry with you.

Note:

We use third form (verb3) of the verb after the modal "Should (Ought to) have." and there is no difference between should and ought to.

They should(Ought to) have listened to me and bought that house last year before the prices increased.

You shouldn't have been watching TV all night yesterday, that’s why you fell so tired now.

Attention!

In negative form, "Ought to" changes to "Ought not to" do not contractoughtn't.

Must Have Done 

Modal "must" has a meaning of necessity, many think that "must have V3" has the same meaning as "should have V3". However; We use must when we talk about a strong possibility based on facts referring to the past.

For Example:

I saw Cynthia crying a few minutes ago. She must have heard the bad news.

I'm quite sure that I put my phone on my desk, now that it's not there somebody must have taken it.

A: Do you know where Martin is?
B: I haven't seen him, but I'm sure he must have left the office as it's 5 o'clock already.


Attention!

Both "must have" and "should have" are perfect modals and they should be followed by past participle (verb3)

They mustn't have arrived (arrive) early, or else they would have called us.

He shouldn't have dropped (drop) out of the school. She regrets doing so now.

More examples for Should / ought to / must have + past participle

·         You should have locked the door before leaving the house. (= You did not lock the door before leaving the house, though that was very important.)

·         They should not have raised the price of essential articles. (= They raised the price of essential articles. That was not right.)

·         He must have been more careful. (= He wasn’t careful though that was absolutely necessary.)

·         He ought to have finished the job last week. (= It was absolutely necessary for him to finish the job last week, but he failed to do so.)

Read the following statements. The first is a statement. The second is a response to it.

·         I didn’t thank him.

·         You should have thanked him.

·         He didn’t ask me before borrowing my car.

·         He should have asked you before borrowing your car.

·         I told him a lie.

·         You ought not to have told him a lie.

·         She behaved rather rudely.

·         She ought not to have behaved rudely.

·         He forgot to bring his passport.

·         He should not have forgotten to bring his passport.

·         The man was under the influence of alcohol.

·         The man should not have been under the influence of alcohol.

·         The boy was rude to the old man.

·         The boy must not have been rude to the old man.

·         He did not prepare for the test.

·         He ought to have prepared for the test.

·         She took the matter too seriously.

·         She should not have taken the matter too seriously.

 Notes

Must is stronger than should. Ought to is similar to should. It is not as strong as must.