OG12-21

dontwannalos

21．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 wenty 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.

很想知道这个HAVING DONE怎么就对了 而且还夹在句子中间呈夹心饼干之态 谢谢

lilingfeng

选a吗？我选a

gmatmba

凡是非谓语动词的完成式都是表示动作发生时间在主句之前。
over the past twenty years 现在完成时标志
Having done, SVO.
S, having done, VO.
都可以的

xiaoxique89

夹心饼干是最好的因为having amassed 修饰的就是Neuroscientists，靠的越近越好

dontwannalos

是不是指 HAVING DONE 前后有逗号就可以成立 如果是句子里面就不对了

dimder

好像HAVING DONE 是不能做定语的，这题可以是因为前面有逗号吗？