Use: have to / don’t have to / needn’t / mustn’t / must
We _ keep the room tidy.
You _ buy tomatoes, we have lots of them.
You _ speak louder, I can hear quite well.
Students _ be late for the lesson.
You _ do the homework on time.

1)Have to

2)Have to

3)Needn't

4)Don't have to

5)Needn't

6)Don’t have to

We are

You are

You don't

Students are

- is the first cake tasty?

- yes, it is.

- was the fourth lesson difficult?

- yes, it was. 

jess hasn't got a big cockerel.

a fox isn't black.