OG-13,语法第25，Neuroscientists求解

whitewoman

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,

我觉得D和E选项的问题都是没搞清楚amass和draw两个动作的主次（即是谓语动词  转移），但OG的解释是
D选项：The final descriptor in present tense, now drawing conclusions … does not fit the opening clause, which is in present-perfect tense (have amassed a wealth …) and seems to modify adulthood.
E选项：Like （D）, this sentence attempts to attach a present-tense descriptor to a present-perfect clause.
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请问，
1"now drawing conclusions..."为何不fit the opening clause？仅仅是因为主句有完成时（参见注解1）故分句中不能有现在分词？而且现在分词drawing的逻辑主语应该为主句主语neuoroscientists，所以不是修饰主句的主语么？怎么会seems to modify adulthood的？非常疑惑。
2顺便再问一下，从整个OG的风格来看，就不大喜欢having这种形式（比如说sc-12，明确的说了having是awkard），为何可以选A呢？

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注解1：
我们来看一个正确的句子，参见OG第十二版SC25，
11. Based on accounts of various ancient writers, scholars have painted a sketchy picture of the activities of an all-female cult that, perhaps as early as the sixth century B.C., worshipped a goddess known in Latin as Bona Dea, "the good goddess."
A. Based on accounts of various ancient writers
B. Basing it on various ancient writers' accounts
C. With accounts of various ancient writers used for a basis
D. By the accounts of various ancient writers they used
E. Using accounts of various ancient writers
这句子中不也是现在分词和完成时主句搭么，当然貌似新版中没有这个句子

hthy25

1、LZ注解1举的例子里和这道题目不一样吧 注解1里的现在分词做的是条件状语吧 而这道题里的D选项 是要把后面也当做一个独立的句子了 现在分词不能这样当独立句子吧 就像解释里说的  now drawing conclusions does not fit the opening clause 不知道表达清楚没有 也不知道对不对。。。
2、另外我也不明白B项的解释里 over the...years appears to he modifying adulthood  以及D项的解释里 now drawing conclusions seems to modify adulthood  怎么都seems to modifying adulthood了呢？

Chuckle

同疑惑，为啥drawing不fit现在完成时呢？

15801218581

Chuckle 发表于 2013-7-23 10:04
同疑惑，为啥drawing不fit现在完成时呢？

Ron大神说，分词的时态与主句时态一致，这题DE选项主句是have amassed，完成时，那分词其实也要表达完成时的含义。而drawing前面是now，明确的现在时的时间标志，两个含义矛盾，所以DE的分词不能fit完成时的主句

bapear

15801218581 发表于 2013-8-15 19:14
Ron大神说，分词的时态与主句时态一致，这题DE选项主句是have amassed，完成时，那分词其实也要表达完成 ...

跟OG上的解释是一样的，还是我还是不能很好领会，纠结啊。