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.
– You must read that book – it’s excellent!
(=recommendation)
Must I really go now?
– 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 go 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 obligatins 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: 2017-12-17T17:50:27+00:00, actualizat: 2017-12-17T17:51:05+00:00 by Colegiu.info