Ответ:

1.

A: I am hungry

B : Why don't you have a pizza ?

A: I can't . I have to go to a basketball in 20 minutes

2.

A: Iam bored

B: Why don't you visit your friends?

A : I can't. I have to finish my homework for tomorrow

3.

A : I am sick

B : Why don't you go home ?

A : I can't. I have to get a maths test this afternoon