[原创]帮忙看一个JJ SC

C D, which one is better?

Before scientists learned how to make a synthetic growth hormone, removing
it painstakingly in small amounts from the pituitary glands of human
cadavers.

(A) scientists learned how to make a synthetic growth hormone, removing
it painstakingly
(B) scientists had learned about making a synthetic growth
hormone, they had to remove it painstakingly
(C) scientists learned how to
synthesize the growth hormone, it had to be painstakingly removed
(D)
learning how to make a synthetic growth hormone, scientists had to remove it
painstakingly
(E) learning how to synthesize the growth hormone, it had to be
painstakingly removed by scientists

C

D is incorrect, since you can not remove "a synthetic growth hormone" from the pituitary glands.

In C, it refers to "growth hormone", but in D, "it" has to refer to "a synthetic growth hormone". And This causes illogic problem, since "a synthetic growth hormone" could not been created yet, then scientists had to get growth hormone from natural source.

楼主能否告诉我最近的VERBAL部分JJ从哪找？谢谢啦！

A: make a synthetic不如直接用动词synthesize有效率；后半句不是完整句，主从句关系不成立

B: before加过去完成时没有道理，learn这个动作实际应该在主句动词时间之后

C: correct

D: 从原句逻辑上看，句意中的hormone并不是被同一群科学家使用，而是表述了一种历史事件之后，hormone就可以被后来的所有人怎样怎样了，所以D从逻辑上有问题。

E: learning的逻辑主语不是hormone

注意：

1、         此题很难，要从逻辑上判断意思，以后遇到主动、被动时态的考点，一定要区分清楚施加对象和被施加对象的合理逻辑关系。什么时候用被动？当找不到主动动作发出者时，一定用被动！以有动作发出者为优
        （自己加的）

还有Before介词+doing，和让步状语从句的省略+doing的区别，When/while（时间）/if/unless（条件）/even though/even if/although（即使）/once＋名词/形容词/完整句 

2、         before介词不能加doing（不构成让步状语从句），只能加时间点