Certainty (deduction), Strong obligation and necessity

Certainty (deduction)

We use must to say that we are sure about something in the present or past

You must be pleased with your exam results. (present)
He must have touched up the photograph. (past)

We use can’t or couldn’t, not mustn’t, in negative sentences

That can’t be Nicole Kidman. She’s not young enough. (present)
They can’t have got lost. They know the area really well. (past)
It couldn’t have been Tom that I saw. (past)

Strong obligation and necessity

We use must/mustn’t to talk about present and future obligations/prohibitions imposed by the speaker, often to him/herself

Payment must be made in cash.
I must get some new shoes.
Must I really go now?
You must read that book – it’s excellent! (=recommendation)
You mustn’t park here. (= prohibition)
You mustn’t eat so much (= strong advice)

Certainty (deduction), Strong obligation and necessity

We use have to/have got to to talk about present and future obligations that are imposed by someone other than the speaker

Note: have got to is more in British than American English.

I have (got) to take my holiday in February.
– Do we have to pay to go in?

We use had to to talk about past and reported obligations of all kinds

– They told us we had to leave our bags in the cloakroom.
We had to stand up when the teacher came in.
– I knew I had to make a decision.

We can also use need to to talk about obligation and necessity

– Do we need to type our work?


Certainty (deduction), Strong obligation and necessity publicat: 2022-10-03T11:50:27+03:00, actualizat: 2022-10-03T13:35:57+03:00 by Colegiu.info