Our English teacher has __________ son.

　　A. a 8-year-old B. an 8-years-old C. a 8-years-old D. an 8-year-old

 Not only his parents but also his sister ________ the museum.

　　A. are going to B. is going to c. are going D. is going

This book is worth _____.

A. to read it B. reading it C. reading D. to read

We should do ___ the teacher told us.

A. because B. like C. as D. since

The number of the people in the world ______ growing faster and faster.

　　A. is b. are C. have D. were

I’m sorry to have kept you ________ for a long time.

　　A. wait b. to wait c. waiting D. to be waiting

 The film __________ for ten minutes when we got to the cinema.

　　A. had already been on B. had already begun

　　C. have already been on D. have already begun

Three years ____ a long time for us students.

A. are B. be C. is D. have been

To a doctor, the most important thing is _______.

　　A. to save b. saving C. to saving D. saved

Can you tell me ________?

　　A. what are they doing that for B.why they are doing for

　　C. why are they doing that D. what they are doing that for