Question

1 Read the examples. Then complete the rules with the bold verbs.
1 You must show them you can change.
2 He mustn't go in there.
3 I have to get home by 9.30 pm.
4 You don't have to be with someone all the time.
5 Why do I have to be with someone?
6 Last Saturday, I had to get home by 10 pm.
7 My mates didn't have to get home until 11 pm.

a We use have to and ............ to talk about rules and things that are necessary. We don't use contractions in the positive: You've to go.
b We use..... when something isn't allowed by a rule.
c We use don't have to when something isn't necessary and ............ when something wasn't necessary in the past.
d. We use ............ to talk about rules in the past. (Must hasn't got a past form.)
e Remember:
You don't have to go. = It isn't necessary. You mustn't go. = It isn't allowed.​

Answer 1

a) We use have to and must to talk about rules and things that are necessary. We don't use contractions in the positive: You've to go.

b) We use mustn't when something isn't allowed by a rule.

c) We use don't have to when something isn't necessary and had to when something wasn't necessary in the past.

d) We use had to to talk about rules in the past. (Must hasn't got a past form.)

e) Remember:

  - "You don't have to go." = It isn't necessary.

  - "You mustn't go." = It isn't allowed.