Prep 124是否虚拟语气？

124. The federal rules aimed at protecting human subjects of medical experiments were established to ensure that patients must be warned of potential risks and an independent panel would evaluate the experiment before it was conducted.

A. must be warned of potential risks and an independent panel would

B. must be warned of potential risks and that an independent panel

C. are warned about potential risks and that an independent panel

D. will be warned about potential risks and an independent panel would

E. would be warned of potential risks and that an independent panel would

A: must ， would不平行

B: must be不能省略；过去发生的事应该用would

C: 同上

D: 同上

E: correct

注意：

1、过去发生的虚拟语气用would

NN的解释说E是虚拟语气，但是我怎么觉得不是虚拟语气吧？只是过去时而已。will 变would就行了。

如果是虚拟语气的话，那和过去发生的相反的事情，按照虚拟语气的要求，应该是：

主句：should/would/could/might + have done,

从句：had +过去分词

这里都不对呀？ 是不是我虚拟语气理解的有问题？？望指教！！