Gmatprep11:求助，定语从句优先于动名词结构吗

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. scientist 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 have to be painstakingly removed by scientists

答案是C，为什么不选D了？ learning的逻辑主语正是后面主句的主语“scientists啊。

还有，大家比较认同sth+过去分词优于sth＋that was/is 过去分词，诸如birds resembling/birds that resemble哪个优先选择了？

这题我一开始也选错了,仔细看了题目以后发现D选项的it指代的是前半句的synthetic growth hormone,导致逻辑意思错误,是growth hormone很难被分离而不是synthetic growth hormone很难分离,因为在那个时候还没有synthetic growth hormone

nice answer!!!thanks a lot!

这个解释经典

请教一下，这个题目主句用过去完成时是不是更加合适一些。描述过去的过去情况。

这个解释比较经典，一把就把D排除了。