—Must I take part in the activity?—No, you _______. You’re too young. You should look after yourself. A. mustn’t B. can’t C. don’t have to
_____ he was tired , ____ he didn’t stop working .
Please _______the light when you leave the classroom.
—Can you answer this question? -- Sorry, I can _________ understand its meaning.
---Hurry up, _______ you will miss the exciting part of the film.
This book _______ be Li Lei’s. Look! Her name is on the cover.