英语四级作文必备知识训练：标点符号的用法
在备考英语四级的过程中，各位考生不仅要注意词汇的积累，句型的掌握，还要注意标点符号的正确使用。下面是小编整理的英语四级作文必备知识训练：标点符号的用法，以供大家学习参考。
冒号的用法
冒号表示停顿，其停顿时间比分号长比句号短。它可用逗号，有时也可用句号代替。尽管现在冒号的使用不如50到75年前频繁，但现在它使用仍很方便，因为它告诉读者其后仍是对上文进一步的陈述。冒号还能产生轻微的戏剧效果。
冒号常用于引出一个词、短语、或完整的句子(子句)来强调，举例解释，或证明刚才所说过的内容。
注意：冒号之后的词可用大写也可用小写字母开头。如果冒号之后的词是另一个完整句子的开始，则用大写字母开头。反之，如果冒号之后的词只是句子的一部分，则用小写字母开头。
例 May I offer you a suggestion: don’t drive without your seat belts fastened.
The thought continued to perplex him: Where will I go next?
用于引出一连串用来解释或强调已叙述过的内容。如：
In the basement, he kept some equipment for his experiments: the test tubes, some chemical agents, three sun-lamps, and the drill.
冒号后常为缩排且不用引号、与全文分离的长引文。
President Jiang Zemin enjoys quoting the first line of Lincoln’s Gettysburg address:
Four score and seven years ago our fathers brought forth on this continent a new nation, conceived in liberty and dedicated to the proposition that all men are created equal.
精典范例
There are only two tragedies in life: one is not getting what one wants, and the other is getting it.
--英国作家Oscar Wide
写作时，切忌这样写：
The four major reasons for the landslide victory were: the candidate’s personal popularity, the enthusiastic support of his party, his stand on budget issues, and the general mood of the nation.
这样用的问题在哪?问题出在冒号用于动词were之后，你可能在英语为母语的人写的报纸或流行刊物中见到这类用法，但它在学术写作中不被大学教师所接受。 在学术论文中，主语补足语或直接宾语应紧跟在冒号之后。主语补足语的修饰词(obvious)使原本存在句子中的问题得到解决：冒号不应紧跟在动词之后。
上面例题中，取得压倒性胜利的四个原因是明显的：the candidate’s personal popularity, the enthusiastic support of his party, his stand on budget issues, and the general mood of the nation.
破折号的用法
用于表示句子正常语序中突然或出人意料的中断。如果意义明确，它也可用于代替括弧或逗号。通常，破折号特别强调它所隔开的部分。
破折号常用于对一长项已表达过的内容进行总结。
例 The day was the longest in her life - or so it seemed to her.
Could you - I hate to ask! - help me with these dishes?
When we left town - a day never to be forgotten - they had a record snowfall.
Most of the paintings in the gallery - in fact all but one - were done in the early 19th century.
What he lacked in intelligence - and he lacked a good deal - he made up for in physical strength.
The three of them were seated at one end of a long dining table that could hold - had once often held - eighteen people.
William Harvey did not discover the circulation of the blood in the body. It was discovered - or rather, always assumed - in China.
More than 600 unforgettable - and often surprising - photographs and Illustrations will rivet your attention, no matter what your age.
破折号常用来总结一系列已表达过的内容。如：
Time and patience - two simple words - yet why are they so hard for me to remember.
分号的用法
分号有时又称为小句号。它表示一个停顿，其停顿时间在逗号与冒号的停顿时间之间。文章如采用许多分号，其风格则变得严肃、正式。为了正确使用分号，有必要先学会辨认主句。当两个主句没有任何连接词(and, but, or, nor, for)连接而出现在同一个句子里，这时最好采用分号使之分离。分号的主要作用很简单，它常用于分离没有连接词连接的句子。但最好不要在从句之间形成如此之强的停顿。如果你要连接从句，而又不愿意用连接词时，则采用分号。
The world is a comedy to those that think; a tragedy to those that feel.
You don’t write because you want to say something; you write because you’ve got something to say.
In the past, boy babies were often dressed in blue; girls, in pink.
Can’t you see it’s no good to go on alone; we’ll starve to death if we keep traveling this way much longer.
John F. Kennedy said at his inaugural speech, "Ask not what your country can do for you; ask what you can do for your country."
Our power to apprehend truth is limited; to seek it, limitless.
Science needs to be lived alongside religion, philosophy, history and esthetic experience; alone it can lead to great harm.
下列各词和短语如用于连接复合句时，常与分号连用：
then however thus furthermore
hence indeed consequently also
that is nevertheless anyhow in addition
in fact on the other hand likewise moreover
still meanwhile instead besides
otherwise in other words henceforth for example
therefore at the same time even now
例：
Being clever and cynical, he succeeded in becoming president of the company; meanwhile his wife left him.
The weather was cold for that time of the year; nevertheless, we set out to hike to the top of that mountain.
According to one national survey, high school boys expected a starting salary of $19,500 for their first full-time job; on the other hand, high school girls expected a starting salary of only $15,000.
括号的用法
括号用于隔开与中心意思相关不紧密的言语。
In New York (I’ve lived there all my life and ought to know), you have to have a license for a gun.
I thought I knew the poem by heart (boy, was I wrong!).
For a long time (too long as far as I’m concerned), women were thought to be inferior to men.
The first time I went driving (do you remember the day?), I was so scared.
其他几种标点的用法
问：如果连续使用两个形容词，可用逗号分开它们吗?
答：在"Singapore is a clean, friendly city state"一句中，逗号代替了"and"。 连续两个形容词同时修饰一个名词时，可用逗号把它们隔开。但当其中一个形容词修饰另一形容词时，不需要用逗号隔开它们：
On my way back home, I stared at the pale blue sky.
问：何时用连字符连接单词?
采用连字符连接的两个词，意思可一目了然。例如，没用连字符的合成词light year，字面意思是一年比另一年不重要;加上连字符，我们就很清楚light-year是光年的意思。
通常，我们在处理名词前两个或多个词的组合时，可用连字符。
例：know-how
ready-to-wear
faster-than-expected production
life-form
state-of-the-art technology
medium-range missiles
当这一群词用作形容词时，仅对它们所修饰的名词之前的词使用连字符。
It was a fast-paced city life.
即City life is fast paced.
Bring me the up-to-date report.
即Bring me up to date.
还有，以"-ly"结尾的副词不用连字符。
Wrong: We do not work with financially-unstable organizations.
Correct: We do not work with financially unstable organizations.
Wrong: We are required to attend all regularly-scheduled meetings.
Correct: We are required to attend all regularly scheduled meetings.
问：你赞成省略缩略语的中间或末尾的句点吗?
答：这是一个关于写作风格和品味的问题，有些编者对缩略语用句点;有些则不用。用与不用取决于你。我的建议是，一旦你决定采用哪种方式，就不宜改变。专有名词中的句点应该保留，姓名之间的圆点应予保留。
问：什么叫不分段句?
答：两个完整的句子间仅用逗号，或不用任何其它标点，这两个句子叫做不分段句。
例：
The air conditioner is broken, we must have it repaired as soon as possible.
How to rid of run-on? Here are a few approaches:
有如下几种方法可消除不分段句 。
The air conditioner is broken and has to be repaired as soon as possible.
(使用连词"and")
The air conditioner is broken; it has to be repaired as soon as possible.
(用分号隔开这两个句子)
The air conditioner is broken. We must have it repaired as soon as possible.
(用句号隔开这两个句子)