上一条说完了逗号，今天继续说其他两个标点，冒号和破折号。
The Elements of Style
Elementary Rules of Usage 惯用法的基本规则
第7-8条：
Rule 7: Use a colon after an independent clause to introduce a list of particulars, an appositive, an amplification, or an illustrative quotation
在独立分句后使用冒号来引出一系列具体事物，一个同位语，一个补充语，或一个说明性的引语
（1）冒号说明后面紧接的部分式和前面的分句密切相关的，冒号的作用比逗号强，比分号弱，比破折号更正式；
它通常跟在独立分句之后，且不应该出现在动词及其宾语或介词及其宾语之间。
The growth of plants needs: water, sunlight, and nutrients. (错误示例，need和后面的名词为动宾结构，中间不能有冒号。正确写法应该是: The growth of plants needs three things: water, sunlight, and nutrients.或者也可以直接去掉冒号)
Understanding is that penetrating quality of knowledge that grows from: theory, practice, conviction, assertion, error, and humiliation. (原文错误示例， from是介词，和后面名词构成的宾语之间不能有冒号，正确写法直接将冒号删掉)
（2）如果有两个分句，后一个是前一个的解释或进一步阐述，则用冒号连接；
There is a consistent attitude on this proposal: the company will face great risks if it was passed.
（3）冒号可用于引入一个支持或辅助前一个分句的引语；
This reminded me of a line from the song of Talyor: "Heartbreak is the national anthem, we sing it proudly." （引用）
The Duke of York read out loudly: "To be or not to be, that is a question." (用于某人直接说话的情况)
（4）冒号具有某些形式功能：正式信件的称呼后，表时间的小时和分钟之间，区分主副标题，《圣经》章节序号……
Dear Mr. Palmer: (信件称呼后)
departs at 10:15 A.M. (小时和分钟之间)
Storm Watchers: The turbulent history of weather prediction from Franklin's kite to El Niño （区分主副标题）
Nehemiah 11:7 （《圣经》章节）
补充：the dependency ratio is 4:10 (表示比例)
Rule 8: Use a dash to set off an abrupt break or interruption and to announce a long appositive or summary
破折号表示突然的停顿或中断，引导一个较长的同位语或总结
（1）破折号是一个分隔符号，它比逗号强，比分号弱，比括号语气更轻松；
The first thing he will do when seeing his ex-girlfriend— if he had any chance to meet her again— is to say sorry. (中断并加入一个较长的新内容，破折号前后可以构成完整句子)
His eyes were caught by the girl—an amazing, cute, and sexy Gypsy maid.（补充说明the girl）
（2）一般仅在更常见的标点符号不够用时才使用破折号；
Violence — the kind you see on television — is not honestly violent — there lies its harm. （不太恰当的用法，更合适的表达应该改为： Violence, the kind you see on television, is not honestly violent. There lies its harm.）
The man's suspicions proved wellfounded — it was not him she cared for — it was his wealth. (不太恰当的用法，更合适的表达应该改为：The man's suspicions proved wellfounded. It was not him she cared for, it was his wealth. 按原文中例句第二个it前是逗号，但根据上一条逗号用法总结，这里其实应该用分号的)
OK，那冒号和破折号也说完啦。
感觉自己做事真是三分钟热度，英文写作分栏才写到第三篇就感觉坚持不下去了额。
路漫漫其修远兮，别想着坚持到底，先拒绝磨磨唧唧。