Have to & Have got to

1 .Use have (got) to in the affirmative/positive form to talk about an obligation, or something

that is necessary to do.

• Have (got) to is always followed by a verb.

• Have to and have got to have the same meaning and can be used interchangeably.

• We have to go to school tomorrow.

Or• We have got to go to

school.

2 .For the negative Use don’t and doesn’t with have to.

• We don’t have to go to school tomorrow! Yay!• She doesn’t have to start her new job until

May 9th.• X: She hasn’t got to start her new job until

May 9th.

Pay attention

•Don't have to means that there isn't any obligation at all,there is no need to do it.

•Don't have to is different from shouldn't and mustn't.

• You don't have to go with me. (You can go with me if you want to.)

You shouldn't smoke. (It is bad for your health.)

3 .Use do/don’t and does/doesn’t in a question.• Do you have to go to school tomorrow?

• Does she have to work tomorrow?

• X: Have you got to go to school tomorrow?

4 .Have to can be used in the simple past:

• He had to spend $2,000 to repair his car after the accident.

• The question

• Did he have to spend $2,000 to repair his car after the accident.

http://www.eclecticenglish.com/grammar/HaveTo1A.html

Modal verbs

• The modal verbs include can, must, may, might, will, would, should. They are used with other verbs to express ability, obligation, possibility, and so on.

Modal Meaning Example

can to express ability I can speak a little Russian.

can to request permission Can I open the window?

may to express possibility I may be home late.

may to request permission May I sit down, please?

must to express obligation I must go now.

must to express strong beliefShe must be over 90 years old.

should to give advice You should stop smoking.

would to request or offerWould you like a cup of tea?

would in if-sentencesIf I were you, I would say sorry.

Rules of the modal verbs

Modal verbs are unlike other verbs

• He can sing very well• I can go to school by

bicycle

1. The form is the same for all persons .there is no –s in the third person singular

• You must stop when the traffic lights turn red

• You should see the doctor

2. Modal verbs are followed by an infinitive without "to"

• Can she drive ?• Should I go home?

3. There is no do/does in the question

• You mustn’t steal.• I can’t swim.

• It won’t rain tomorrow .

4. To form negative add n’t . There is no don’t/doesn’t

Will not = won’t

• I could swim when I was three .

5. Most auxiliary verbs refer to present and future

•Only ( can ) has a past tens , ( could)