He’s read this book before, ?A. hasn’t he B. doesn’t he C. isn’t.
---Why is he so happy?---He __________ the volunteering club and works for the old people.
---The girl is practicing English, ___________?---Yes, she is. She is good at English.
---___________ tall building it is! ---It has over one hundred floors.
Look at the picture. We are supposed to____________.
More and more people have a low-C life and the air is _________ than before.