16.Mr. Hall understands that ______ maths has always been easy for him， it is not easy for the students.

　　A. unless

　　B. since

　　C. although

　　D. when

　　17.When you answer questions in a job interview， please remember the golden rule： Always give the monkey exactly ______ he wants.

　　A. what

　　B. which

　　C. when

　　D. that

　　18.______ is going to America for further study.

　　A. He is said that

　　B. People said that he

　　C. It was said he

　　D. It is said that he

　　19.Mary ______ be in Paris，for I saw her in the town only a few minutes ago.

　　A. mustn‘t

　　B. can’t

　　C. shouldn‘t

　　D. may not

　　20.— The room is so dirty. ______ we clean it?

　　— Of course.

　　A. Will

　　B. Shall

　　C. Would

　　D. Do