Writing Better English for ESL Learners

15. Present Susan has to get to work on time.
    Past
    Present Perfect
    Past Perfect
    Future

Auxiliaries are followed by a verb in its infinitive form minus the particle

word to. Look at these examples with the infinitive to work.

able to work ought to work can work

have to work supposed to work must work

need to work may work

want to work should work

When you use one of the auxiliaries with a verb, you tell to what degree of

obligationsomeone has to carry out the action of the verb. Look at the follow-

ing sentences. The first one shows the least degree of obligation. This is some-

thing someone doesn’t have to do. The last sentence shows the greatest degree

of obligation. This is something that someone absolutely must do.

We may return the books. (Least obligation. It’s our choice.)

We can return the books. (Little obligation. It’s our choice.)

We are able to return the books. (Little obligation. We have the ability to

do this.)

We need to return the books. (Slight obligation.)

We ought to return the books. (Little obligation. But this would be a

good idea.)

We should return the books. (Little obligation. But this would be a

good idea.)

We are supposed to return the books. (Some obligation. Someone has

suggested we do this.)

We must return the books. (Greatest obligation. It is our duty to do this.)

We have to return the books. (Greatest obligation. It is our duty to do this.)

When you add an auxiliary to a sentence, you should use the same tense as

the original verb. For example: “John found [past tense] a good book.” When

you add have toto that sentence, you say, “John had to [past tense] find a good

book.”

20 Writing Better English