157. By the time human beings become fully aware of the importance of the ozone layer, it __ seriously damaged. A. will be B. will have been C. is D. has been 158. I should very much like to have gone to that party of theirs.but __ A. I'm not invitedB .I will not be invited 159. The last person __ will have to turn off the lights. A. have left B. left C. leaving D. to leave 160. You will spend at least one year working abroad __ you can find out how things operate overseas. A. because B. so as to C. so that D. so long as 161. When wet. __ A. these old papers give off a bad smell B. we get a bad smell from these old papers C. a bad smell comes from these old papers D. there is a bad smell coming from these old papers 162. He couldn't give a __ explanation for his actions. A. satisfied B. satisfying C. satisfactory D. satisfaction 163. Thanks to his parents' __ he tried his best to win a place at a university. A. approve B. approval C. disagreement D. rejection 164.To attract the waiter's attention, wait until you __ and raise you hand slightly A. catch his eye B. can attract him C. pay attention to him D. take advantage of hin 165.Don't __ to conclusions, we don't yet know all the relevant facts. A. hurry B. jump C. rush D. run