【题目】We went through a period ________ communications were very difficult in the rural areas.
A.which
B.whose
C.in which
D.with which

【答案】C
【解析】句意：我们度过了一段在农村通讯很困难的时期。先行词是period，后面的定语从句中缺少时间状语，要用when或in which，相当于in the period表示时间，作句中的状语。所以答案是C。