知识点
GMAT的SC部分常会遇到四种标点：
逗号(，)是最常见的标点，也是最难使用正确的标点，不过GMAT考试很少以标点作为考点并通过逗号来判断正确选项。关于逗号记住：

不要用逗号连接两个句子。

当句子中两个谓语动词发起者是同一个人时，不要在and 前面加上逗号。

◆ Wrong: Earl walked to school, AND later ate his lunch.
◆ Right: Earl walked to school AND later ate his lunch.
◆ Right: Earl walked to school, AND HE later ate his lunch.

分号(;)连接两个相关的语句，每个部分都可以独自站立作为一个句子，但是如果句意上前后两者是有从属关系的则不能用分号：

◆ Right: The dam has created dead zones, WHERE fish have disappeared.
◆ Wrong: The dam has created dead zones; fish have disappeared.

分号又常常同些连接副词一起使用，如however, therefore, or in addition ，注意这些词和连词and 等又完全不相同，所以对于这些词，常常使用分号进行连接：

◆ Wrong: Andrew and Lisa are inseparable, THEREFORE, we never see themb apart.
◆ Right: Andrew and Lisa are inseparable; THEREFORE, we never see them apart.

而另一种比较少用的分号使用方法是将同一类的东西分开，而这些东西之间是用逗号分隔的：

◆ Wrong: I listen to Earth, Wind & Fire, Wow, Owls, and Blood, Sweat & Tears.
◆ Right: I listen to Earth, Wind & Fire; Wow, Owls; and Blood, Sweat & Tears.

冒号(:)为之前的事提供进一步的解释，说明。冒号前的通常是一个句子，可以独立存在，而冒号后则无需是句子，而有时会在冒号后加入namely 或that is。
I love listening to many kinds of music:
namely, classical, rock, rap, and pop.

要说明的部分离冒号越近越好：

◆ Worse: Three factors affect the rate of a reaction: concentration, surface area, and temperature.

◆ Better: The rate of a reaction is affected by three factors: concentration, surface area, and temperature.

破折号( - )是一个灵活的标点符号，GMAT考试中偶尔会用到。有时破折号可以代替逗号来使用：

By January 2, 2000, the so-called “Y2K problem” was already widely considered a joke—although the reason for the non-event was the huge corporate and governmental investment in prior countermeasures.

但有时候破折号又是必须的：

My three best friends—Danny, Jimmy, and Joey—and I went skiing.

这句话如果用逗号就会让人误以为有七个人go skiing 。破折号有时用来解释或重复之前句子的某个部分，但不像冒号需要紧跟着需要解释的词前面：

Post-MBA compensation for investment bankers tends to surge far ahead of that for management consultants—by tens, if not hundreds, of thousands of dollars a year.

上面的这个例子中by tens, if not hundreds, of thousands of

dollars a year 解释句子前面的far。
试题
In 1988, the Council on Economic Priorities began publishing Shopping for a Better World, with the simple thesis of consumers having the power to change companies by the simple expedient of refusing to buy.

A. with the simple thesis of consumers having
B. which had the simple thesis of consumers having
C. where the thesis was simple: consumers having
D. with a thesis that is a simple one: consumers have
E. whose thesis was simple: consumers have
试题
正确答案：E
题目释义：the Council began publishing SFBW, whose thesis was simple：consumers have…
考点:
定于从句，同位语从句，句子结构
选项分析
A. 用with引导的非限定性短语做伴随状语错误，而事实上，thesis是Shopping for a Better World这本书的主题，不能作为前面整句话的伴随；thesis后面用of不好，thesis变成了某一类特定的consumers，而合理含义上应该是一个thesis应该是某个现象，因此要改为that从句(同位语从句)，或者用冒号来引出从句。
B. Thesis应该用同位语从句修饰；thesis of sb. doing sth.累赘，结构含糊。
C. 关系代词where指向Shopping for a Better World不恰当；冒号后面要用完整句子，缺少谓语。
D. with的错误同A，后面a thesis that is a simple one不简洁。
E. correct。