12.he began to try every material ___ the best way to work it out
A known to find B knowing to find C knowing finding D known finding 选哪个，为什么其它选项不行
13.Who are you waiting for?
____ us a lecture this afternoon
A The professor wants to give
B The professor will give
C The professor about to give
D The professor to give选哪个，为什么其它选项不行
14.Easy as we made it ____ the important to keep earth in place,some villagers wouldn’t listen
A to understand
B understood
C understanding
D understan选哪个，为什么其它选项不行
15.有没有just to do这个词组？
16.he lost his job three months ago;____,he was seriously injured in an accident last week
A in the first place
B to make matters worse
C on the country
D in other words选哪个，为什么其它选项不行
