老题再问。OG13-97.中reducing修饰的问题，求大神帮忙解答，大谢啊

果果henan

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 sometime 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,

选项a中有句解释The structure makes that clause appera to be an awkward and rhetorically puzzling suparate assertion that the writer has appended to the prior claim about what the anthropologists believe. The agent or cause of reducing is unclear.
我的看法：
问题一：我觉得reducing没有错啊，因为：reducing在句尾并且前面有逗号，因为根据默认语法规则，"comma+v-ing"必须修饰前面那个从句，也就是that之后的从句（引用baby姐的话http://forum.chasedream.com/GMAT_SC/thread-650744-4-1.html）那就是our ancestors suffered an event这件事reducing their numbers
and thus our genetic variation. 我觉得这在句子意思上也是说的通的。求指教，我哪里错了？
问题二：破折号的具体用法是什么？在这里可以理解成是对于"population bottleneck"--的解释说明吗？OG的解释是believe that X ——that Y平行。应该怎么理解？

求大神解答啊，不胜感激~

onlyspirit

。。。。
不是这个原因吧 A之所以错的主要原因是因为没有That，ing可以修饰动作，正是suffer这个动作导致结果。结果用ing形式来表达是正确的。
有了that让句子更加clear，这才是考点吧。

alexzeze

hemodata 发表于 2013-7-22 16:09
确实是修饰的our ancestors suffered an event这一句话
但是，是修饰这一句话的主语+动词
也就是ancesto ...

感谢啊！

joybb

hemodata 发表于 2013-7-22 16:09
确实是修饰的our ancestors suffered an event这一句话
但是，是修饰这一句话的主语+动词
也就是ancesto ...

谢谢O(∩_∩)O~

hemodata

joybb 发表于 2013-7-18 18:58
顶起，我的迷惑点和楼主的一样。希望NN们来解答啊

确实是修饰的our ancestors suffered an event这一句话
但是，是修饰这一句话的主语+动词
也就是ancestors suffer

但是从逻辑来看，造成人口下降的是宾语event
而不是ancestors suffer这个action
所以这句话的逻辑就此错掉

babybear说的修饰从句，意思是修饰的那个从句的主语+谓语，强调不是修饰主语这一个单词
很显然在他的例子里，leading to修饰也不是stress啊

hemodata

青瓦台BOSS 发表于 2013-3-17 15:03
但是，在白勇书里，ing分词短语在句末1）伴随动作：状态和功能，与句子的谓语动作同时发生，逻辑主语等于主 ...

akaa说的很清楚，修饰那一句话的意思是，修饰主语+谓语，而不是修饰那一句话中的某个单词

joybb

顶起，我的迷惑点和楼主的一样。希望NN们来解答啊

jhanas

青瓦台BOSS 发表于 2013-3-17 15:03
但是，在白勇书里，ing分词短语在句末1）伴随动作：状态和功能，与句子的谓语动作同时发生，逻辑主语等于主 ...

同问。我觉得青瓦台BOSS 解释的很好。很迷惑，A为什么不对

青瓦台BOSS

顶！

召唤斑竹和NN们

青瓦台BOSS

但是，在白勇书里，ing分词短语在句末
1）伴随动作：状态和功能，与句子的谓语动作同时发生，逻辑主语等于主句主语
2）伴随结果，整个句子是原因，到时分词动作产生，无逻辑主语
所以本题中的reducing their numbers是伴随结果，不应该修饰的是our ancestors suffered an event这一句话，并且而不造成什么歧义么？

同样，在LZ的贴的贴子里，Baby姐举的例子是：“Biochemists found thatgeldanamycin induces cellular stress, leading to cell death. 这句话，"leading to cell death" is the direct and immediate consequence of the entire action of the preceding clause "geldanamycin induces cellular stress", and it applies to the subject within that clause (geldanamycin). ”

“, leading to cell death ”  没有逻辑主语，因为很明显geldanamycin不是他的主语，他是修饰geldanamycin induces cellular stress这整个从句的

还有一周就要考了，求NN来解惑！！

楼主也许可以这样想：
reducing如果作现在分词修饰前面的句子的话，那么他的逻辑主语就是主句主语，那么这个句子变啥样了呢？
Our ancestors reduce their numbers?
这个是不是说不通呢

-- by 会员 akaa (2013/1/11 19:51:28)