Complete the following sentences with must or have to in the correct form.
MUST + INFINITIVE is often used for personal opinions and feelings. We can use MUST to talk about the present or future, but not the past. I must remember to buy a present for my sister. (my opinion) She must do it next week. (future)
MUSTN'T (MUST NOT) + INFINITIVE refers to an obligation no to do something. MUSTN'T can be used to talk about the present or future, but not the past. You mustn't drink cold drinks and eat ice cream. (prohibition) You mustn't use this phone for private calls. (prohibition)
HAVE TO + INFINITIVE is used to express a strong obligation. It is used for facts, not for personal feelings. We can use HAVE TO in all forms. In Ireland, you have to drive on the left. (strong obligation) Does she have to go away so soon? (present simple) I'll have to speak to him. (future simple) She had to work yesterday. (past simple) He may have to go to Holland. (modal verb)
1) doesn't have to 2) must 3) will I have to 4) mustn't 5) didn't have to 6) Must 7) has to 8) mustn't 9) had to 10) have to