用标点分隔完整的想法

完整的想法有主语和动词，自己就能表达意思。当两个完整的想法放在一起时，必须用比逗号更强的东西把它们分开。这项技能出现在拼写、标点与校对单元的每一项较长写作任务里。

有哪些办法可以分隔两个完整的想法？

有四种可靠的办法。把它们当作一份短菜单来记。

1. **句号（full stop）**加大写字母：The bus was late. We missed the start.
2. 分号（semicolon）： The bus was late; we missed the start.
3. 逗号加连接词（and, but, so, yet, or）：The bus was late, so we missed the start.
4. 让一个想法依附于另一个的连接词（because, although, when）：We missed the start because the bus was late.

两个完整的想法之间，单独一个逗号永远不在菜单上。

怎样测试一个逗号？

遮住逗号后面的词。前半部分能独立成句吗？

再遮住逗号前面的词。后半部分能独立成句吗？如果两半都可以，这个逗号就太弱了。

例题

改正这一段。

The library closes at five, we have only an hour. Nadia wanted a novel, Ben needed a science book. The shelves were crowded however they found both.

第 1 步。 “The library closes at five” 是完整的。“we have only an hour” 也是完整的。中间只有逗号。改用 “so”：The library closes at five, so we have only an hour.

第 2 步。 “Nadia wanted a novel” 和 “Ben needed a science book” 都完整，而且关系紧密。用分号合适：Nadia wanted a novel; Ben needed a science book.

第 3 步。 “however” 连接两个完整的想法，却没有任何标点。在它前面用分号，后面用逗号：The shelves were crowded; however, they found both.

改正后：

The library closes at five, so we have only an hour. Nadia wanted a novel; Ben needed a science book. The shelves were crowded; however, they found both.

要提防的错误

常见的失误，是把 “however”、“therefore”、“also” 当成像 “and” 一样的连接词。

错误写法： I revised all week, therefore I felt ready.

“Therefore” 并不能连接这两个想法，所以逗号仍然是拼接。正确写法有：“I revised all week, so I felt ready.” 或 “I revised all week; therefore, I felt ready.”

自我检测

改正每个句子的标点。

1. The museum was quiet, we could hear our own footsteps.

2. Amir trained daily, however he did not make the team.

3. 哪一句是对的？(a) She was tired, she kept working. (b) She was tired, yet she kept working.

接下来学什么？

句子分隔正确之后，学习区分粗心失误和真正的知识缺口：distinguish a typing error from a knowledge gap。关于连接词背后的语法，请看句子构建与改写。

老师能听出你朗读草稿时在哪里停顿，而标点最适合放在停顿的地方。这是一对一线上第二语言英语补习会做的事情之一。