问题补充:
There are a number of cases family members or friends quarrel with each other and become enemies.
A. that
B. which
C. where
D. when
答案:
A. that
B. which
(答案→)C. where
D. when
解析:句意:又很多家庭成员和朋友彼此争吵成为敌人的情况。这里使用了定语从句,先行词是cases,定语从句中缺少的是地点状语(in the case)所以用关系副词where引导定语从句,选C。