单选题The factory was built&nbs

问题补充：

单选题Thefactorywasbuiltinasecretplace,around_________highmountains.A.which wasB.it wasC.which wereD.them were

答案：

C解析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。