1．The Comma逗号

The role of the comma is certainly an important one．In some ways，the comma is the reader's map for each sentence．In any case，as you will see，without properly used commas your writing will often force the reader to take a detour．Comma serves two purposes in sentences—to separate and to set off．

逗号的功能极其重要。它是读者正确理解句意的重要参考。在所有标点符号中，它的使用率最高，用法也最复杂。它既可以表示句子内部的一般性停顿，也可以在句子结构需要的地方表示停顿。

a．Clauses of compound sentences

A compound sentence is one that has two or more independent clauses．Use a comma between the independent clauses jointed by and，but，for，or，nor，or yet．

在并列句中，并列连词and，but，for，or，nor或yet等词前用逗号。

Compare:

Catherine photographs all our products，but she is out of the office this week．

Catherine photographs all our products but is out of the office this week．

Our company tries to produce high-quality products，and it expects to get a fair profit for doing so．

Our company tries to produce high-quality products and expects to get a fair profit for doing so．

I worked last Saturday，and I probably will work next Saturday．

I worked last Saturday and probably will work next Saturday．

b．Items in series

A series consists of a minimum of three words，phrases，or clauses．For clarity，always use a comma after each item in the series except the last．Thus the last comma should be immediately before the conjunction that precedes the last item in the series．

表示三个及以上事物列举时，每一项后必须用逗号，并且最后一项要用并列连词。

Microprocessors，monitors，and diskettes have been delivered to the computerroom．

Jim spent most of the week meeting prospective clients，showing them our products，and describing our services．

Jim introduced the program，Jan gave a slide presentation，and Greta made the closing re-marks．

Note:If the conjunction is repeated before each item，then no comma is needed to separate the item．

但假如每一项中都有连词重复，则无须逗号。

Our number one sales office may be Denver or Houston or Manchester．

Whenever the abbreviation etc．ends a series，be sure to use a comma before and after it．

任何时候句中使用etc．表省略，前后都必须用逗号。

Sales，profit，revenues，etc．，were discussed at this morning's session．

She gave several reasons for increasing the budget estimate—higher costs，overhead，declining market，etc．

c．Introductory words，phrases，or clauses

To signal the reader to slow down，use a comma after an introductory word，phrase，or clause．

有时逗号在句中起舒缓语气的作用。

(1)Introductory word

First，we must discuss the change in buying patterns．Second，we must survey typical customers．Finally，we must choose an advertising agency to represent us．

(2)Introductory phrase

To qualify，you must be a resident of this state．

To get your copy，just complete and return the enclosed form．

Knowing the exact cost，Karen tried to correct Bill．Believing he was right，Bill kept insisting his prices were correct．

Overwhelmed by the project，the director requested more assistance．Alerted to the problem，management assigned help right away．

With the additional clerical help now available to us，our department should no longer have such backlogs．

(3)Introductory clause

If we receive your deposit by February 9，we will reserve one set for you．

Because Everett will be out of town，Sherry did not buy a ticket for him．

While Mrs．Carl is here，let's discuss this trust fund．

d．Nonrestrictive modifiers

Nonrestrictive elements are those words，phrases，and clauses that can be taken out of a sentence without affecting the identity of the item described，and that may explain，contrast，or amend some part of the sentence;but they are not necessary to the sentence．

非限制性定语从句是对主句的补充和说明，通常必须用逗号隔开。

My father，who retired recently，has moved to Florida．

Julie，hearing her name called over the intercom system，went into Mrs．Kane's office．

My employer，Mr．Johnson，is the new president of the Chamber of Commerce．

His brother，not his cousin，has been appointed to the new post．

This information is not，so far as I know，classified．

e．Explanatory elements

Explanatory elements include geographic names，dates，degrees or titles，and explanatory expressions accompanying direct quotations．

一些地理名词、日期、学位、头衔以及直接引语前通常用逗号。

Eric sent the letter to Salem，Oregon，rather than to Salem，Massachusetts．

Friday，March 15，is the last day to submit quotations．

Martin Luther King，Jr．，was killed on April 4，1968．

“I am concerned，”Gretchen wrote，“that you did not receive my order．”

f．Miscellaneous uses

(1)Use commas to separate repeated words，two numbers coming together，numbers of four or more digits，tag questions，and inverted named．

重复的单词、两个数字连用、四位及以上的数字、附加疑问句以及颠倒的名姓中也要用逗号。

In 2014，5，000 acres of land will be sold from the ranch．

I can still file an application，can't I?

No，no，the sales record is not right!

(2)Use commas to set off direct address and to show omission of words．

逗号可用于称谓呼语，或表示省略成分。

Thank you，Mrs．Harriman，for paying your bill so promptly．

In 1991 our company paid a yearly dividend of $ 3．40;in 1992，$ 4．15;in 1993，$ 4．35．

(3)Do not use commas between subjects and verbs．

在主谓之间通常不用逗号隔开。

Avoid:The story that Tracy heard，is entirely different．

Use:The story that Tracy heard is entirely different．

(4)Do not use commas between the last adjective in a series and the noun that is modified．

在一连串形容词修饰的名词和最后一个修饰词之间不用逗号。

Avoid:The bright，handsome，toy is extremely popular in South America market．

Use:The bright，handsome toy is extremely popular in South America market．

(5)Do not place a comma between two items in a series that are joined by a coordinate conjunction．

已经由并列连词连接的两个成分之间不用逗号。

Avoid:I wanted to finish the office work，and to leave early．

Use:I wanted to finish the office work and to leave early．

Avoid:Ken said that he was wrong，and that he wished to apologize．

Use:Ken said that he was wrong and that he wished to apologize．