The first use of atomic weapons was in 1945,and their power___inreased enormously ever since.

题目

The first use of atomic weapons was in 1945,and their power___inreased enormously ever since.
A.is B.was C.has been D.had been
我选了C
是因为前后两句时态并列都是过去吗?

答案

ever since:表从那时到现在,或自从的意思,其通常与完成时态连用,因为主句表达的是过去的内容,所以这里要用过去完成时,自从那时起,那时指的是The first use of atomic weapons was in 1945.