You _________ keep quiet in the library. (must or mustn't)
must
What musn't Tom do?
Tom mustn't sleep in class.
John ________ swim. He hates water. (can or can't)
can't
Can elephants fly?
No, they can't.
Should he watch TV all day?
No, he shouldn't.
What must he do?
He must do his homework.
Jill _________ drive. She's a taxi driver. (can or can't)
can
You _________ throw rubbish around. (must or mustn't)
mustn't
I _________ run very fast. I'm the fastest girl in the class. (can, should or must)
can
What can't he do?
He can't ride a bike.
It's hot. You _________ open the window. (can, should or must)
should
What should he do in the morning?
He should get up early.
You ________ go to class late. Teacher will be angry! (must or mustn't)
mustn't
What can Mary do?
She can play the piano.
You __________ wear a helmet when riding a motorbike. (can, should or must)
must
We __________ eat fruit and vegetables. They are healthy foods. (should or shouldn't)
should
It's cold. You __________ put on a coat and a scarf. (should or shouldn't)
should
You __________ play with fire. (should or shouldn't)
shouldn't