旧prep sc1 74

wanghongliang

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

答案是D，可是我觉得该是C啊，请NN指点！

triangel8866

...are not,...,but are not前后结构要平行~~but是连词，连接独立的两个句子，前后主语相同可以省略。C选项中but引导的句子，缺少动词啊

psychepsyche

补一个are让not...but...结构形式上更加对称吧，意思更加清楚

wanghongliang

可是这不是are not A but B结构吗？B前怎么还加are啊？

appleontree

not……but……的词组用法，not不在助动词后，not X but Y，X和Y绝对平行
not……but……的非词组用法，not必须在助动词后，not X but Y，X和Y不必对等，比如be not X, but (be) Y，but做连词，并列前后两个谓语，其中be可以省略，但要在不产生歧义的基础上，比如OG12的81题，解释中就说不用补出助动词are，多余（因为有by……不会产生歧义的）；而此题如prep笔记中所说“ but可能作为介词,产生because they enhance reproduction or survival, but simply random by-products的歧意”，所以必须补出are。
昨天刚好复习了这个语法点~欢迎拍砖~

wanghongliang

谢谢！