大全987-no.576的句子结构

windaisy

         People have discovered the principles of solar energy whenever fuel becomes scarce and expensive but will forget them every time a new source of cheap energy is developed.   

(A) have discovered the principles of solar energy whenever fuel becomes scarce and expensive but will forget

(B) have discovered the principles of solar energy whenever fuel has become scarce and expensive but they forget

(C) discovered the principles of solar energy every time fuel becomes scarce and expensive, forgetting

(D) discover the principles of solar energy every time fuel became scarce and expensive, but they forget

(E) discover the principles of solar energy whenever fuel becomes scarce and expensive but forget

答案选e, forget与discover平行用but连接，那句末的is developed是谁的谓语，是every time引导状语从句还是它后面省略了when?请指教，谢谢！

rhod

forget与discover 平行。every time后面是个时间状语从句，与划线部分的whenever从句平行。

参考Longman里对every time的解释:

every time
whenever
- The roof leaks every time it rains.

绿水长流

如果e改成 (E) discover the principles of solar energy every time fuel becomes scarce and expensive but forget 是对是错呢?是不是比原答案更平衡了？因为看到有个帖子说every time 有歧义,不明白嗄~~请教，谢谢！

绿水长流

继续请教，谢谢xiexie

paopao

是一样的

参考Longman里对every time的解释:

every time
whenever
- The roof leaks every time it rains.