平行

step two：寻找 splits（选项间的差别），根据 splits 快速排除。（一个 trick：一个常见的情况是，splits 出现在句首句尾）

step three：寻找单个选项内的问题。一般难题都是五个选项都不一样，没有 splits.

B、常考的一些我们不知道的点：

1、COMMA + which 的指代   


Todate, GMAC has only used "which" to modify two kinds of things:

"- Noun”

"- Noun + prep + other noun” 此处的prep + other noun必须修饰逗号前的noun而非主语。

口语导致的常见错误：which 不能指代逗号前的整个句子。

举例：

Letter to S.H.D, which were written… (正确)

I took the picture of my dog in 1995, which I kept for years.(错误)

The cottontail rabbit population in Orange County, California, has increased unchecked in recent  years，which is a result of removing…(错误)

2、V-ing

三个考点：1、与主动作相关 2、同时发生/因果  3、暗示逻辑主语

关于2的常见错误：

xxxxxxxxx, previously __ing...

xxxxxxxxx, later __ing...

xxxxxxxxx, now __ing...

xxxxxxxxx, ultimately __ing 


唯一不符合该规则的 V-ing：including 

If used to introduce a partial list of something, "INCLUDING" should NOT be considered an "__ing modifier". 

In fact, you should think of the word "including", in these contexts, as though it didn't end with "-ing" at all.

comma + "including"...

...elaborates on a NOUN that comes before it (possibly a noun + modifiers);

AND

...is followed by only SOME, NOT ALL, of what that noun encompasses.

举例：

In gym class we performed ten different body-weight exercises, including push-ups, pull-ups, and planks.

v-ing作为gerund  vs. verbal noun （楼主懒就直接贴 Ron 的解答了）

The verbal noun (like “the exposure”) are IMPERSONAL—they DON’T convey the idea that the subject is directly involved. 提到 action 的 subject.

Gerunds (like “exposing”) are personalized-- they DO convey the idea that the subject is directly involved in the process.

GMAT 对 V-ing 修饰规则较模糊，有时可跳过前面的名词修饰。

Like the great navigators who first sailed around the Earth gathering information about its size and the curvature of its                  surface, astronomers have made new observations that show with startling directness the large-scale geometry of the universe.

3、COMMA+V-ing （仍然直接贴 Ron 的解答）

bare-bones summary： 

These modifiers describe, in some reasonably way, the PREVIOUS ACTION previous CLAUSE. 

Assignment of the –ING action in comma+ -ing modifiers 

Matt’s sister slapped him, angering the children father. 

The SUBJET of the previous clause should be the source/do-er of the action described in the-ING 

Matt was slapped by his sister, angering the children’s father

Dad was mad at Matt (presumably for being hit by a girl.

Can the COMMA+ING ever modify the touching noun?

If the modifier comes after a clause, then no...

If it just follows a noun (NOT a clause), then yes, it can...   

The injured birds, flapping their wings frantically, searched for a safe placed land.

4、确指（it, they）与概括