2. Complete the conversation with 'must, can't or might'.
Andy: Someone is knocking at the door.
Susan: It (1)
be the delivery man. I ordered a pizza.
be him!
Andy: But you ordered the pizza five minutes ago. It (2)
Susan: Oh, that's right. Then it (3)
be my brother
Andy: No, it (4)
be your brother, he is in basketball training.
Susan: You're right! Let's open the door, it (5)
be important.