大全101

Avatar

Although the Supreme Court ruled as long ago as 1880 that Blacks could not be excluded outright from jury service, nearly a centry of case-by-case adjudication has been necessary to develop and enforce the principle that all juries must be drawn from "a fair cross section of the community"

(A) has been necessary to develop and enforce the principle that all juries must be

(C) is necessary to develop and enforce the principle that all juries must  (A)

请问这里为什么一定要用has been 而不能用is呢?

lilyzy

nearly a centry 是关键.

hhjc

这个指示词真怪异啊,害得我没敢用完成时