自从新SAT改革以来，标点符号在文法（Writing and Language Test）中一直是比较热门的考点，清楚各标点符号的功能及用法很重要。那么逗号（comma）该怎么用呢？今天小编就带大家来熟悉一下这两类标点符号的特点以及常考的题型。

逗号在句中的作用：

1、用于连接一个句子的并列成分。

He is a tall, strong and outgoing guy.

2、用于分隔同位语。

One of my good friends John, a good student, will attend the competition.

3、用于分隔句首或句中的状语,状语从句和其省略形式。

His face, when I arrived there, turned red gradually.

If it rains tomorrow, the sports meeting will be cancelled.

Under the tree, a boy had a nap.

例题部分

【例题】

First-generation college students are banding together to create on-campus communities; because they find the support system very helpful.

A.NO CHANGE

B.communities: because

C. communities;

D.communities,

后面because引导状语从句，本应该用逗号隔开，原句用分号所以错误，因此只能选D选项。

1、用于分隔非限制性定语从句。

He admires the man very much, who is an famous professor in the research.

【例题】

Sam was searching all over the internet for the sarcastic meme: which he wanted to send to his girlfriend.

A. NO CHANGE

B. meme:

C. meme,

D. meme

Which后面引导的是非限制性定从，修饰meme所以正确的标点符号应为逗号。

2、用于分隔插入语。

The man, however, dislike the animated movie Nezha.

那么在SAT考试中，常见的错误有哪些呢？

1、不能连接两个独立句子（Independent clauses）。

2、不能隔开主谓（SV）

【例题】

The nutritional content of this sports drink is better than that of Caimanade, it contains electrolytes that reduce lactic acid.

A. NO CHANGE

B. Caimanade; it contains

C. Caimanade it contains

D. Caimanade; it contains,

这题原句逗号连接了“The nutritional…” 和”It contains…” 两个句子，所以用法是错的。D选项逗号隔开了” contains”和”electrolytes” 这俩主谓，因此是错误的。那么这里加分号是可以的，因为分号可以连接两个独立的句子。

掌握标点符号的用法还需多多练习，

归纳总结。