请教PREP-P2-21

21.   (25520-!-item-!-188;#058&002357)

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

请问D错在哪里啊,答案是C.

这道题好大的陷阱，乍一看绝对中计。

scientist have to painstakingly remove的是growth hormone,不是synthetic growth hormone。只有C，E在这一点上是正确的，但E的逻辑主语错误。

论坛有PREP笔记的，MM可以去看一下。

‘惯性’陷阱；

synthesize the growth hormone和make a synthetic growth hormone意思相差很多，

我说一下后者的不合常理之处，

在学会make一个人造的H之前，必须把这个人造的H从身体里remove掉；