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

(B) was necessary for developing and enforcing the principle of all juries being

(C) was to be necessary in developing and enforcing the principle of all juries to be

(D) is necessary to develop and enforce the principle that all juries must be

(E) will be necessary for developing and enforcing the principle of all juries being

ANS: A

请教各位牛牛，为什么D不对呢? 这句话的意思是? 感谢~

我的看法是～

此题考necessary的用法，be necessary for SB to do ST：

B）此选项用 for 错误！

C）用法错误

D）时态错误，a century 以来不断发生的事要用完成式

E）时态错误

希望能对您有帮助，谢谢。