句子结构完整与否 fragment/run-on

猴在学gmat · 发表于 2022-3-14 10:48:30

335. Sixty-five million years ago, according to some scientists，an asteroid bigger than Mount Everestslammed into North America, which, causing plant and animal extinctions, marks the end of the geologic era known as the Cretaceous Period.
A. which, causing plant and animal extinctions, marks
B. which caused the plant and animal extinctions and marks
C. and causing plant and animal extinctions that mark
D.an event that caused plant and animal extinctions, which marks
E.an event that caused the plant and animal extinctions that mark
解析：E
This sentence describes a two-part sequence of events, the second of which has led to a particularcategorization of geological time. In order to clarify that it is not the first event(asteroid strike) thatproduced the time division (end of the Cretaceous Period), but the first event's consequences(biological extinctions), the sentence needs an appositive form to restate the content of the mainclause (an event), followed by a two-part chain of relative clauses (that caused ... that mark ..).
A.The antecedent for the relative pronoun which is ambiguous; it is therefore unclearwhat marks the end of the Cretaceous Period.
B.The antecedent of which is unclear;the compound verbs caused and marks fail toindicate that the extinctions, not the asteroid strike, are significant markers of geologicaltime.
C.Following the conjunction and with a participial rather than a main verb isgrammatically incorrect because it violates parallelism and produces a fragment at the end of the sentence.
D.Which, referring to extinctions, should be followed by a plural verb.
E.Correct.The sentence is unambiguous, and the verbs agree with their subjects.

想请问一下C的句子结构，不太理解为啥是句尾句子结构不完整。按答案来的话是an asteroid bigger than··· and causing plant and animal extinctions that mark the end of···。这里我理解句尾是plant and animal extinctions mark the end of ··，所以认为句尾完整的。而前半句只有 n（an aster···），没有v，我感觉是前半句不完整。
还请NN指正！！谢谢！！

敦敦酱 · 发表于 2022-3-14 14:23:38

这里必须阐明一个很重要的概念就是verbing by itself is not a verb!, that’s a modifier. 举个例子。

The asteroid was slamming into North America.这句话的结构：subject + verb + object

The asteroid slamming into north America, 这句话的结构: noun + modifier。”slamming into north america modifies the asteroid” 注意这里的名词asteroid甚至不一定是主语。

Be + verbing是真正的动词形式，verbing by itself is merely a modifier.

然后C第二个错误其实更容易发现，时态都不一致了。

causing plant and animal extinctions 在句意里应该和前面哪个clause平行？should be “slammed into North America”, here is the tense disagreement. I don’t see the reason to use a simple past “slammed” and a present participle “causing”, seriously why? These 2 events happened in the same time according to context. It really should be “… caused extinctions”.

猴在学gmat · 发表于 2022-3-22 15:16:19

敦敦酱发表于 2022-3-14 14:23
这里必须阐明一个很重要的概念就是verbing by itself is not a verb!, that’s a modifier. 举个例子。

Th ...

我明白啦！！谢谢nn！！
我又仔细看了一下解析和您的回复，意思是不是and 后的causing是分词但这里缺少动词，导致此处句子不完整~

敦敦酱 · 发表于 2022-3-23 10:25:46

选项C是一个完整的句子。不完整的句子我们称为fragment。两个独立的句子没有conjunction链接我们成为run-on。以上两个情况都是必错的。

但是这个选项C既不是fragment,也不是run-on。划线前面的部分已经是完整的句子了。最最伤筋动骨的问题是这里的and。太多人做SC遇到平行结构只去纠结mechanics，也就是所谓的语法，而不去斟酌平行结构是否符合逻辑（是否符合美国人的逻辑）。GMAT对语法的考察是0%，对你没看错GMAT不考语法。尤其是近些年随着难度越来越高更不会再考语法了。

举个例子:

James performed poorly on his GMAT exam and scored very low on the Verbal section.
这句话平行么？好像平行是吧，语法很正确对吧。但实际上这是一个必错的句子。。。因为and必须联结两个优先级一样的事物，如果有一个是另一个的sub clause，使用平行结构就是不符合（老美的）逻辑的。比如这句话里面语文分低是阐述为什么James总分低，语文分数低是Gmat总分低的一个sub clause。
James performed poorly on his Gmat exam, scoring very low on the Verbal section. 这样正确
这里的scoring（Verbing 形式）就是修饰前面整个clause的。

但其实真题不会这么简单，你会需要去判断（老美的思路）对于这句话应该是怎样的一种逻辑。比如这道题里面, 咱们就先把什么时态啊句子完不完整放一边，句子的逻辑应该是：
There was an asteriod, this asteriod slammed onto earth, this slam then caused the great extinction.
It's not the asteriod itself caused extinction! asteriod itself cannot cause extincion. So you can't say "asteriod slammed onto earth and caused extinction", because that would illogicaly place (slammed onto earth) and (caused extincion) to parallel, which is nonsense.

学会掌握gmac老头的逻辑，学会掌握美国人的思路。

猴在学gmat · 发表于 2022-4-27 20:55:52

敦敦酱发表于 2022-3-23 10:25
选项C是一个完整的句子。不完整的句子我们称为fragment。两个独立的句子没有conjunction链接我们成为run-on ...

明白啦，说的很清楚！感谢NN！！

句子结构完整与否 fragment/run-on

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