Punctuation is used to mark the cadence, pauses, and tone in written English. In other words, punctuation helps us to understand when to pause between fully formed ideas when speaking, as well as organize our thoughts in writing. English punctuation marks include:

在书面英语中，标点符号用来标记韵律、停顿和语调。换言之，标点符号有助于我们理解说话时在完全形成的思想之间停顿的时间，以及在写作中组织我们的思想。英文标点符号包括：

period, comma, question mark ? exclamation mark ! colon :semi colon ;
句号，逗号，问号？感叹号！冒号：分号；

Beginning English learners should focus on understanding the period, comma, and question mark. Intermediate to advanced student should also learn how to use colons and semi colons, as well as an occasional exclamation mark.
初学英语的人应该把重点放在理解句号、逗号和问号上。中级到高级的学生也应该学习如何使用冒号和分号，以及偶尔的感叹号。

This guide provides instruction on the basic rules of using a period, comma, colon, semicolon, question mark and exclamation point. Each type of punctuation is followed by an explanation and example sentences for reference purposes.
本指南介绍了使用句点、逗号、冒号、分号、问号和感叹号的基本规则。每种标点后面都有一个解释句和例句，以供参考。

Period
句号

Use a period to end a complete sentence. A sentence is a group of words containing a subject and predicate. In British English a period is called a "full stop".
用句号结束一个完整的句子。句子是包含主语和谓语的一组词。在英国英语中，句号叫做“句号”。

Examples:
例子：

He went to Detroit last week./They are going to visit.
他上周去了底特律。/他们要去参观。

Comma
逗号

There are a number of different uses for commas in English. Commas are used to:
英语中逗号有许多不同的用法。逗号用于：

Separate a list of items. This is one of the most common uses of a comma. Notice that a comma is included before the conjunction "and" which comes before the final element of a list.
将项目列表分开。这是逗号最常用的用法之一。请注意，逗号包含在列表最后一个元素之前的连词“and”之前。

Examples:
例子：

I like reading, listening to music, taking long walks, and visiting with my friends./They would like books, magazines, DVDs, video cassettes, and other learning materials for their library.
我喜欢看书，听音乐，散步，和朋友们一起参观。/他们喜欢书，杂志，DVD，录像带和其他学习材料为他们的图书馆。

Separate phrases (clauses). This is especially true after a beginning dependent clause or a long prepositional phrase.
单独的短语（从句）。尤其是在从句或长介词短语之后。

Examples:
例子：

In order to qualify for your certificate, you will need to take the TOEFL exam./Although he wanted to come, he wasn't able to attend the course.
为了获得证书，你需要参加托福考试。/尽管他想来，但他没能参加这门课。

Separate two independent clauses that are connected by a conjunction such as 'but'.
用连词如“but”连接的两个独立从句分开。

Examples:
例子：

They wanted to purchase a new car, but their financial situation would not allow it./I'd really enjoy seeing a film this evening, and I'd like to go out for a drink.
他们想买一辆新车，但他们的经济状况不容许。/今晚我真的很喜欢看电影，我想出去喝一杯。

Introduce a direct quote (as opposed to indirect speech i.e. He said he wanted to come ...).
介绍一个直接引语（与间接引语相反，他说他想来…）。

Examples:
例子：

The boy said, "My father is often away during the week on business trips."/His doctor replied, "If you don't stop smoking, you run the risk of a heart attack."
男孩说：“我父亲经常出差在外。”/他的医生回答说：“如果你不戒烟，你就有心脏病发作的危险。”

Separate appositives (a noun, or noun phrase) or non-defining relative clauses.
单独的同位语（名词或名词短语）或不明确的关系从句。

Examples:
例子：

Bill Gates, the richest man in the world, comes from Seattle./My only sister, who is a fantastic tennis player, is in great shape.
比尔盖茨，世界上最富有的人，来自西雅图。/我唯一的妹妹，是一个出色的网球运动员，状态很好。

Question Mark
问号

The question mark is used at the end of a question.
问号用在问题的结尾。

Examples:
例子：

Where do you live?/How long have they been studying?
你住在哪里？/他们学习多久了？

Exclamation Point
感叹号

The exclamation point is used at the end of a sentence to indicate great surprise. It is also used for emphasis when making a point. Be careful not to use an exclamation point too often.
感叹号用在句子的结尾，表示非常惊讶。它也被用来强调时，提出一点。注意不要经常使用感叹号。

Examples:
例子：

That ride was fantastic!/I can't believe he is going to marry her!
那次旅行太棒了！/我不敢相信他会娶她！

Semicolon
分号

There are two uses for a semicolon:
分号有两种用法：

To separate two independent clauses. One or both of the clauses are short and the ideas expressed are usually very similar.
把两个独立的从句分开。其中一个或两个从句很短，表达的意思通常非常相似。

Examples:
例子：

He loves studying; he can't get enough of school./What an incredible situation; it must make you nervous.
他喜欢学习；他不能得到足够的学校教育。/多么不可思议的情况；这一定让你紧张。

To separate groups of words that are themselves separated by commas.
将本身由逗号分隔的词组分开。

Examples:
例子：

I took a holiday and played golf, which I love; read a lot, which I needed to do; and slept late, which I hadn't done for quite a while./They plan to study German, for their travels; chemistry, for their work; and literature, for their own enjoyment.
我度假打高尔夫球，这是我的爱好；我读了很多书，这是我需要做的；我睡得很晚，这是我很久没有做过的事了。/他们计划学习德语，旅行；化学，工作；文学，自娱自乐。

Colon
冒号

A colon can be used for two purposes:
冒号可用于两个目的：

To provide additional details and explanation.
提供额外的细节和解释。

Examples:
例子：

He had many reasons for joining the club: to get in shape, to make new friends, to lose some weight, and to get out of the house./She gave notice for the following reasons: bad pay, horrible hours, poor relations with colleagues, and her boss.
他加入俱乐部有许多理由：保持身材，交新朋友，减肥，离家出走。/她发出通知的理由如下：工资低，工作时间糟糕，与同事和老板关系不好。

To introduce a direct quote (a comma can also be used in this situation).
引入直接引语（在这种情况下也可以使用逗号）。

Examples:
例子：

He announced to his friends: "I'm getting married!"/She cried out: "I never want to see you again!"
他对朋友们说：“我要结婚了！”/她喊道：“我再也不想见你了！”
（来源：沪江英语，作者：Summer）