537.We first met on a train in 2000.We both felt immediately that we ______ each other for years.
A.kenw
B.have known
C.had known
D.know
538.I'm sure Andrew will win the first prize in the final.
I think so.He ______ for it for months.
A.is preparing
B.was preparing
C.had been preparing
D.has been preparing
537.答案是C;that从句中know的动作发生在felt之前，故用过去完成时。
538.答案是D;根据for months和will暗示，prepare从过去持续到现在，并将继续下去，故用现在完成进行时。
