Modal Verbs: Grammar Rules

We use have/has to for             . We can also say I have got to ... with the same meaning.

Have to/Must mean the same when we are talking about rules and obligations, i.e.           obligation. But must generally refers to           obligation (i.e. the speaker feels something is necessary).

Must is not very common in           forms. Must is followed by the infinitive without to.

Bear in mind that the silent 't' in mustn't is quite obvious.

No obligation

Students often confuse don't/doesn't have to with mustn't which is a              . Don't have to means 'it is not necessary to do something, but you can do it if you wish'.

Advice

Should/Shouldn't is used when we want to give a         opinion, telling someone the best thing to do. We can ask for someone's opinion with Do you think I should ...? or using the modal verb Should I ...? The silent letter 'l' in should and shouldn't should be noted.

Bear in mind that should/shouldn't and had better are followed by the infinitive without …     .

Ought to is a …       modal verb. This is because unlike modal verbs the main verb is followed by 'to', but like modal verbs the form of the main verb does not change with the person.

Ought to is slightly more …         and less commonly used than should.

Had better is a two-word modal verb which refers to the …          or the future (but can't be used to talk about the past).

We can           'had" (e.g. you'd better).

Had better has the same meaning as …         and …           but it also implies more strongly that there will be a problem if you don't follow this advice.

Permission

The modal verb ..      is used to convey the idea of permission (can also conveys the ideas of possibility and ability).

We can also use could, may and might for …             .