小逗号的大学问

逗号（comma）是英语中最常见，也最容易误用的标点符号。在一句话中，逗号代表语气的停顿，它的基本功能是帮助读者快速理清句子结构，使句义清楚明了，以免产生误解或歧义。逗号使用不当，不仅会影响信息的传达，甚至还有可能闹出笑话。

概括起来，英语中的逗号主要有以下几种用法。

1. 用于分隔一系列项目（三个或三个以上）

·The street vendor sold watches, necklaces, and earrings.

·Everyone hollered, hooted, backslapped, and jumped into the air.

在上面的例子中，and前面的逗号叫牛津逗号（Oxford comma）或序列逗号（serial comma）。到底该不该加这个逗号一直是语法界争论不休的问题。有趣的是，尽管名为Oxford comma，但在英式英语的标准用法中，这个逗号是省略的（当然，Oxford University Press除外），而在美式英语中则通常保留。

2. 用于连接独立分句的并列连词前

常见的并列连词可以用一个首字母缩略词来概括：FANBOYS，分别代表For、And、Nor、But、Or、Yet和So。

·Guion Bluford was the first African American to fly in space, and he was a decorated Air Force veteran.

·I like wearing comfortable clothing, so I buy oversize shirts and sweaters.

·I asked for cream in my coffee, but the waiter did not give my any.

3. 用于分隔主句前的引导成分（introductory elements），引导成分可以是单词、短语或从句

·However, she did not do a good job.

·Just in time, Sherry applied the brakes and avoided a car accident.

·Hearing her name called, Kisha went to the receptionist’s desk.

·Although he had been first in the checkout line, Deion let an elderly woman go ahead of him.

4. 用于分隔插入成分（parenthetical elements）

插入成分指打断句子的正常顺序，提供解释或补充性信息的单词、短语或从句。插入成分需要放在两个逗号之间。

·I am sure, however, that it will not happen.

·London, the capital of Great Britain, lies astride the Thames in South Central England.

·The vinyl car seat, sticky from the heat, clung to my skin.

·The spread of the coronavirus, by droplets or physical contacts, is containable.

5. 用于分隔修饰同一名词的形容词，或修饰同一形容词的副词

·The Brite brothers were ingenious, self-reliant men.

·It was blindingly, glaringly hot.

需要注意的是，只有当两个形容词或副词之间可以用and连接时，才能用逗号隔开。

6. 用于分隔直接引语

·“For my first writing assignment,” said Scott, “I have to turn in a five-hundred-word description of a stone.”

·“I’m sorry,” said the restaurant hostess. “You’ll have to wait.”