19. This is the key _____..  19. This is the key _____.  A. which you are looking for   B. for which you are looking  C. for that you are looking   D. you are looking for which选B为什么错?

问题描述:

19. This is the key _____..
  19. This is the key _____.
  A. which you are looking for   B. for which you are looking
  C. for that you are looking   D. you are looking for which
选B为什么错?

look 是不及物动词,接宾语要跟介词,look for 不能分开
正确答案是A