问题补充:
The factory was built in a secret place, around high mountains.
A. which was
B. it was
C. which were
D. them were
答案:
A. which was
B. it was
(答案→)C. which were
D. them were
解析:考查定语从句。around which were high mountains是一个由 介 词+which 引出的非限制性定语从句,而在该从句中,主语是 high mountains ,around which是表语,所以句子谓语应用复数were,而不是用单数 was.