求GMAT语法题一道

题目

求GMAT语法题一道
188.(26379-!-item-!-188;#058&001961)
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

答案

having+done结构不能作后置定语
The first text books_______for teaching English as a foreign language came out in the 16th century.
A.having written B.to be written C.being written D.written
此处A项不能作后置定语 应选D项.
比较你的题目A的话这种分词所表示的动作发生在句中谓语动词所表示的动作之前,在句中作时间或原因状语用
Neuroscientists have amassed.are now drawing .你这一个句子里有两个动词而且没有连接词,是不对的.