Neuroscientists, having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are now drawing solid conclusions about how the human brain grows and how babies acquire language.

(A) Neuroscientists, having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are
(B) Neuroscientists, having amassed a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years, and are
(C) Neuroscientists amassing a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years, and are
(D) Neuroscientists have amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood,
(E) Neuroscientists have amassed, over the past twenty years, a wealth of knowledge about the brain and its development from birth to adulthood,

错选D,应为A
A中用having觉得怪怪的，D不是没用语法错误吗？

 

首先，这里的having是没有问题的

我们在讨论GMAT语法的时候曾经说过，完成时态的ing形式不能做定语，但是这里的having amassed做的是伴随状语修饰的后面的are drawing，这是可以的，也就是说申请科学家正在得出结论，而得出结论的过程的伴随过程是在过去的20年中积累了很多关于什么什么的财富。

D选项你可以认为没有绝对语法错误，但是D选项将原句里面所想要表达的意思反了过来

原句中 having amassed 是一个修饰成分，主要表达的意思是 draw conclusion，也就是说主要表达的是 ： 在过去20年大量积累知识的情况下，现在神经学家正在下结论，这个表达很合理

但是D选项变成了 神经学家，在现在得出结论的情况下，在过去20年中积累了很多东西 这个意思就不好了

A是正确选项 BCE的错误都很明显

希望这样的解答能够帮助你
来自http://www.beyondgmat.com/index.php/bbs?func=view&catid=5&id=994