PREP问题！最新发现！！之三！

mycontrol01

Paleontologist Stephen Jay Gould has argued that many biological traits are not the products of natural selection, favored due to their enhancement of reproduction or survival, but that they are
simply random by-products of other evolutionary developments.

(A) due to their enhancement of reproduction or survival, but that they are
(B) due to the reproduction or survival they enhance, but they are
(C) because they enhance reproduction or survival, but
(D) because they enhance reproduction or survival, but are
(E) because of enhancing reproduction or survival, but are

这道题的CD选项很难判断呢
我选C啦  我仔细想了下，D也算是平行的，但是既然前面有ARE了为什么还非要加上去呢

mycontrol01

补充一下 答案是D！

boalgmat

不太清楚 划线部分  not。。。but。。平行结构   中间是插入语

cx_ding

根据语法笔记，due to， because of等词后面只能跟简单名词，不能跟分词或从句构成的名次成分。
不知道这样回答对不对。

heslington

'Due to' modifies a noun, and  'Because of'  or 'Because' modify a verb. As a result, options with 'Due to' should be eliminated. E is out also because it does not have a clear subject. Between C and D, the latter is better because  'but are not' can make the sentence clearer in the presence of the modifier.

nute

are not A, but B
are not A, but are B

这两种结构哪种好呢？我觉得是第一种好，答案却是第二种。求解