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题库 / Prep2007E2-SC-21
Before scientists learned how to make a synthetic growth hormone, removing it painstakingly in small amounts from the pituitary glands of human cadavers.
scientists learned how to make a synthetic growth hormone, removing it painstakingly
scientists had learned about making a synthetic growth hormone, they had to remove it painstakingly
scientists learned how to synthesize the growth hormone, it had to be painstakingly removed
learning how to make a synthetic growth hormone, scientists had to remove it painstakingly
learning how to synthesize the growth hormone, it had to be painstakingly removed by scientists
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CD 区分：
it 做代词，则需要代指全面名词包括其定语，那么在C中，it 代指growth hormone； D中代指synthetic growth hormone（合成的）。所以D错
1. if the subject of a verb is unknown or irrelevant, use the passive voice.
2.In the problem at hand, the original sentence, along with answer choices B and D, indicate that scientists removed "a synthetic growth hormone" from cadavers. This is nonsensical, as something synthetic, by definition, does not come from a natural source. Thus, A, B, and D can be eliminated based on their lack of clarity.
排除掉ABD，CE里面比最优，E: "before learning"修饰的是scientists,和主句主语矛盾。
"A 主句没有谓语动词
E learning的逻辑主语错误
BD中it指代的是前面的一整个名词a synthetic growth hormone，但事实上应该指代growth hormone
"
D:1.it指代synthetic growth hormone，这种合成的激素不能从人体这种自然条件下remove出来
2.learning逻辑主语是scientists，科学家们研究出来如何合成这种激素✔️
但在此之前，从人体内提取激素的不一定是科学家，可能是医生。这种无法确定主语是谁的要用被动语态表达。
这里其实从逻辑上来说是不知道谁去提取这个荷尔蒙的，所以c更合理
在CD之间选，实际上就是时态的区别
"learning how to synthesize the growth hormone, scientists had to remove it painstakingly" -- dont know if its wrong, but I would still prefer C.
because, of the word "had" which suggests two actions in the past..so ideally, it should be "learned".
A/B/D，it指代a synthetic growth hormone，错误
C，it指代the growth hormone，ok
［之前错过一次了，这次又错了。。。。］
⚠️it的指代问题和句意
A：主句缺少谓语动词
B：it指代的是前面的一整个名词a synthetic growth hormone，但事实上应该指代growth hormone
C：✅这里的名词是growth hormone，所以it指代growth hormone
D：错误同B
E：变成了it learn，逻辑错误
choice b,d: it指代的是 a synthetic growth hormone-一种合成的生长荷尔蒙。incorrect
choice c, it指代growth hormone-生长荷尔蒙。correct
A：句子不完整
B:had learned过去完成时，时态错误。且it指代synthetic growth hormone，错误。
D:同B，it指代错误。
E:变成了it发出learning这个动作。
if the subject of a verb is unknown or irrelevant, use the passive voice.
choice e is wrong, because it starts out with an initial modifier lacking a subject; such modifiers MUST modify the noun IMMEDIATELY FOLLOWING the comma. in the case of choice e, this would mean that 'it' (referring to the hormone itself) learned how to make the hormone. that's crazy.
选项A 句子无主谓
选项B Before后跟过去完成时态错误，因为learn应该在主句动作remove时间之后;it指代synthetic growth hormone不符合逻辑。
选项C 正确 Before scientists learned how to synthesize the growth hormone,it had to be painstakingly removed in small amounts from the pituitary glands of human cadavers.
选项D it指代synthetic growth hormone不符合逻辑。
选项E learning 逻辑上不修饰IT
it 完全指代，找准指代对象
C & D 主要是弄清指代问题
C: scientists learned how to synthesize the growth hormone, it had to be painstakingly removed
这里的it指的就是前面的the growth hormone
D: learning how to make a synthetic growth hormone, scientists had to remove it painstakingly
这里的it离得太远，且指代的是a synthetic growth hormone，句意就变成了“在科学家们学会如何制造合成荷尔蒙之前，他们只能将这种合成荷尔蒙从...中提取”，而本意不是提取合成荷尔蒙，而是最开始只能提取荷尔蒙，后来学会了合成荷尔蒙，句意！
1. E：句子开头是learning，由此可见主句的主语应该是人scientists，而E选项中主句的主语是it，因此排除E；
2. B：Before 从句的时态是过去完成时态，而句子中没有表示过去的过去的时态词。排除B；
3. A：A选项使得整个句子不是个independent 句子，排除A;
4. D：remove it中it指代的是a synthetic growth hormone，但根据句子意思可知应该是remove 人体中的growth hormone，而不是synthetic growth hormone。此外remove这个动作的发出者应该是doctor，而不是scientists。由此排除D。
做题时多注意句子的逻辑意思。
D中的it指代了a synthetic growth hormone，都没合成怎么可能取出，所以synthetic是多余的
mark
D中的it指代了a synthetic growth hormone，都没合成怎么可能取出，所以synthetic是多余的
can't agree more~~ it指代a synthetic growth hormone，不符合逻辑
一语中的!
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D选项错在哪里？
图形背景原则。
C和D的主从句顺序没有改变呀？D如何错在图形背景原则呢？
哦哦，不好意思，说错了。是remove的发出者。从人类的腺体移除荷尔蒙的其实并不是科学家，而是医生。所以，这句话的意思是，在科学家研发出怎么合成荷尔蒙之前，荷尔蒙只能从人类身上提取。这个提取工作不一定是科学家做。
恩，明白了。
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