求教v-ing结构中逻辑主语的问题

vianvee

今天在刷OG的时候碰到了两题相似的v-ing结构的句子，有点想不明白，题如下。


Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"—at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.

(A) at some time in the past our ancestors suffered an event, greatly reducing their numbers
(B) that at some time in the past our ancestors suffered an event that greatly reduced their numbers
(C) that some time in the past our ancestors suffered an event so that their numbers were greatly reduced,
(D) some time in the past our ancestors suffered an event from which their numbers were greatly reduced
(E) some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly,



A mutual fund having billions of dollars in assets will typically invest that money in hundreds of companies, rarely holding more than one percent of the shares of any particular corporation.
A. companies, rarely holding more than one percent B. companies, and it is rare to hold at least one percent or more  
C. companies and rarely do they hold more than one percent  
D. companies, so that they rarely hold more than one percent  
E. companies; rarely do they hold one percent or more



第一题应选B，第二题应选A。

我想问的是，做这类v-ing结构的句子，从句的主语是逻辑主语吗？
第一题A选项的逻辑主语是the genetic homogeneity evident吗？第二题的逻辑主语是a mutual fund吗？
另外，第二题的B到底错在哪里，找了一遍CD论坛，也没有对B 详细的解释，另一个帖子说B错在at least 和or more上面，可我觉得错也只能错在it is rare to hold上面，不求甚解，大神帮帮忙！！

番番爱GMAT

语法渣渣的，不过我觉得第一题里面，-—后面就是一个新的句子了，解释的是"population bottleneck"。

第二题我觉得就是at least和or more意思重复了...不确定你觉得it is rare to hold哪里错了....

DD肚肚

http://forum.chasedream.com/foru ... 4%E6%8A%98%E5%8F%B7
这个网页是介绍破折号的作用，因为破折号可以充当冒号或者分号，我觉得第一题的破折号应该是相当于分号，因为后面at some time in the past our ancestors suffered an event中suffered是一个谓语动词。也就是第一题里面有两个主句，因此greatly reducing their numbers and thus our genetic variation.应该是修饰它前面的主句的主语，即event；
第二题我觉得是改变的句子的重心。因为分词结构是表伴随，不是整个句子的重心，但是换成了and前后两个句子就是并列的，是一样重要了，所以就不符合原文的主句（重心）+伴随状语有不完善的地方请大家指正

boring0706

我觉得第一题的破折号是表强调的。这里不用判断破折号的用法，排除法也能做题。A选项，不管表强调还是当冒号分号用，reducing都是修饰ancestors的，杀。C选项，so that语意不对，杀。D选项，from which感觉怪怪的，这个我解释不好。E选项，破折号不管表强调还是当冒号分号用，都不对。【刚开始准备GMAT，说得不对，还望见谅】