doing 形式的伴随结果。

windconniewj

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,
答案是A，不选D，prep08语法笔记188的接受是drawing 不是has amassed的直接结果，为什么不是？不理解。求好心人解答

lyhong508

句子的连接，主从句的选择和逻辑关系都跟句意有关
背景是过去二十年一直怎么做的，v-ing引导的插入语提供一个背景
用完成时的原因有二，时间段，强调过去对现在的影响
而重点是现在怎么做的，所以谓语该给现在。过去影响现在
而且说实话， 这个句型挺经典的，高中貌似背过。。

foreverqueen11

having引导的第二个逗号是插入语，不是句子主干，可以跳过，那么如果你选D，则主句就是Neuroscientists now drawing……缺少谓语are 应该是are drawing才对