52. There has been an 8% d__________ in his income because of the financial crisis.

51. I must a __________ to you for not being able to meet you at the airport.

20. The day________ he was looking forward________ in the end.

　 A. when; to come　　　　　　　 B. which; to come

　 C. when; to came　　　　　 　　D. which; to came

19.---Who ________ it be that is knocking at the door?

---It________ be Mother, but I’m not sure.

　 A. can; must　　　　　 B. can; may　　　　　　　 C. must; can　　　　　　　　　 D. may; must

18.If you cheat in the exam, you could hardly________ it.

A. throw away　　　 　 B. run away　　　 　 C. get away with　　 D. stay away from