20. It is what and how much you eat and how much physical activity you do during the day__________ determines whether you gain, lose or keep your weight.

A. when 　　　　　　　　 B. how 　　　　　　　　 C. which 　　　　　　　 D. that

19. I __________ all hope, but by giving myself one last chance I found victory in my efforts.

A. have given up　 　　　　　　　　　　　　　　 B. gave up 　　　　　 C. had given up 　　　　　　　　　　　　　　　 D. give up

18. Wildlife in the Amazon forests ___________ be very dangerous, so you have to be extremely careful.

A. would　 　　　　　　 B. can 　　　　　　　　 C. could 　　　　　　　 D. should

17. __________ in the traffic jam, he was likely to be late for the job interview.

A. Being stuck 　　　 B. Having stuck 　 C. Stuck 　　　　　　　　 D. Sticking