—Listen! Peter is singing in the classroom!
—It _____ be him. He has gone back to his hometown.

---There is somebody knocking at the door. Who________ it be?
---I’m not sure. It ________ be a postman.

I ______ follow you. Would you please repeat it?

All passengers______go through safety check before they take a plane.

— ____ you sing the English song?
— Yes, I can.

For the safety, everyone _________ obey the traffic rules when he is driving or walking.

– Is your brother playing computer games, Nick?
– He ________ do that because the computer doesn’t work.
A. mustn’t                 B. shouldn’t               C. can’t

Tell me and I’ll forget. Show me and I       not remember. Let me try and I’ll understand.
A. can                   B. may                C. must

— The Queshi greenway has become a popular place for Shantou people on the weekends.
— That’s right. And you ________ drive your car on it because it is a path for cycling and walking. 

Who is the man over there? Is it Mr. Wu?
— It ________ him, but I am not quite sure.