The factory was built in a secret place, around high mountains.
A. which was
B. it was
C. which were
D. them were
网友回答
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.