【讨论】非限制性定语从句与插入语（同位语）区别

soulcake

In laboratory rats, a low dose of aspirin usually suffices to block production of thromboxane, which is a
substance that promotes blood clotting, but not seriously interfering with the production of prostacyclin,
which prevents clotting.
(A) which is a substance that promotes blood clotting, but not seriously interfering
(B) a substance that promotes blood clotting, but not seriously interfering
(C) a substance that promotes blood clotting, but does not seriously interfere
(D) which is a substance to promote blood clotting, but does not seriously interfere
(E) which is a substance that promotes blood clotting, but not a serious interference
该题答案是 C
有G友问到，D为什么不对，我解释为 to promote blood clotting 语气有变 带目的，相对主动语态的表达 promotes blood clotting 显得wordy。但如果 D 选项是 Which is a substance promotes blood cotting,.... 后面一样 ，哪该选哪个呢？
个人觉得理应也是C，但非限制性定语从句 和同位语（插入语）区别在哪儿呢？非限制性定语从句从属关系，起补充说明，可以去掉，不影响原句意思。做为thromboxane同位语，起补充说明，也可去掉。这下就难以区分了，求讨论~~

cocoloop

没什么区别，都是对前面名词的补充说明，但在这里，C明显优于D，更简洁明确

chasekai

我也有和楼主同样的疑问
prep笔记对D的解释是这样的：“ but does…更像是跟is a substance…并列,从而作为了thromboxane的谓语动词,改变了原句的意思“  我对这个不是很理解。

jay871750293

对，同意沙发~
C比D简洁

记得OG12里有一道题也是这样的，答案解释说：a sth作同位语& which is a sth非限制定从都成立时，选前者，因为在这里which is没有意义，显得wordy

zhouzuozz

同意楼上的，d选项which is wordy， 而且，a substance to do也显得awkward