MODAL AUXILIARIES

Auxiliaries verb sometimes called modal auxiliaries. They are helping verb that express a wide range of meaning (ability, permission, necessity, etc.) most of the modals have more than one meaning. They are followed by the simple form of verb, they are followed by to, the main verb never has final –s.
Modals and related verb phrases add meanings to verbs. Below are some of those meanings:
1. Ability/Availability
· future: will be able to
· present: can, am/is/are able to
· past: could, was/were able to

2. Requests
· present/future: can, could, will, would

3. Permission
· future: will be allowed to
· present/future: may, can, could, am/is/are allowed to
· past: could, was/were allowed to

4. Possibility
· present/future: may, might, could
· past: may have, might have, could have

5. Impossibility
· present/future: couldn’t, can’t
· past: couldn’t have

6. Advisability
· present/future: should, ought to, had better
· past: should have, ought to have, had better have

7. Expectation
· present/future: should, ought to
· past: should have, ought to have

8. Necessity
· future: will have to
· present/future: must, have to, has to
· past: had to

9. Lack of Necessity
· future: won’t have to
· present/future: don’t have to, doesn’t have to
· past: didn’t have to

10. Prohibition
· present/future: must not, may not, cannot
· past: could not 

11. Logical Deduction (=Probability)
· present: must, have to, has to
· past: must have, have to have, has to have