— Must they clean and tidy the classroom now? — No, they      . It       after school in the afternoon.

We ________the difficulty together, but why didn’t you tell me?

—Must I finish the exercise this afternoon?—Yes, you ______, but you ______ finish it now.

 You’d better ____ football in the street.

—Must I buy lunch at school?—No, you needn’t. You __________ bring your own lunch if you want to.