52258 modals of possibility and certainty

We use MAY, MIGHT and COULD when something is possible.
It may/might rain tomorrow
When we are sure that something certain, we use MUST
I have put on some weigh, I must lose some kilograms
When we are sure that something is not possible or is impossible,
we use CAN’T
He doesn’t answer the phone, he can’t be at home

WRITE ‘must’ or ‘can’t’
1.- Where is your sister? She ……. be in her bedroom doing her
homework.
2.- Tom’s life …… be easy. He earns little money in his job.
3.- This book isn’t mine. It …….. belong to one of your friends.
4.- The child has just eaten so he ……. be hungry again.
5.-Your dad …… smoke a lot of cigarettes because he coughs.
6.-That blonde girl ……. be Paul’s wife. She is too young.
7.-The food in this restaurant is really delicious. They ….. have a good
chef.
8.-Look! This is Vincent’s new car. He …… have bought it.
9.-People carry umbrellas so it ……. be raining.
10.- My car doesn’t start. Something ……. be wrong.
11.-That man wears very old clothes. He …….. be a rich man.