22. -Did you reach the top of the mountain?

　 -Yes. Even I myself didn’t believe I could make ______.

A. that　　　　　　　　　　　　 B. it　　　　　　　　　　　　　　　　　 C. one　　　　　　　　　　　　 D. any

21.-I have got a pain in my back.

　 -No wonder. You ______ in front of the computer too long.

　 A. have worked　　　　　　　　 B. are working　　 C. have been working　　　 D. Worked