问题补充:
So far nothing Tom. I want to know the reason he hasn’t written to me.
A. heard from; why
B. has been heard from; why
C. was heard from; that
D. has heard from; that
答案:
A. heard from; why
(答案→)B. has been heard from; why
C. was heard from; that
D. has heard from; that
解析:含有so far的句子应该时现在完成时态;reason作先行词,定与从句应该用that引导。