问问大家，为什么E要那个“ it “呢？

7. Dental caries and gingivitis can be exacerbated not only by the foods patients eat but also by when the patients eat them.

(A) not only by the foods patients eat but also by when the patients eat them

(B) by not only the foods patients eat but also by when the patients eat them

(C) not only by the foods patients eat but also by time when the foods are eaten

(D) by not only the foods that are eaten by patients but also by the times the foods are eaten

(E) not only by what patients eat but also by when they eat it

同时，为什么C不对呢？

c有多处问题：

（1）time 前至少该有个the

(2)are eaten 不好吧.被动语态！

（3） time when the foods are eaten 中的when因该是关系副词，在此指代time也有问题。

另外，it 在此指what,eat作为吃东西的吃时，是及物动词。