comma splice 指的是 两个完整的句子只用逗号连接。这是 First Language English 写作中最常见的标点错误之一，通常出现在你写得很快、思路一路往前冲的时候。
这一课属于句子控制（sentence control）。干净地修正 splice 能保护任何写作中的准确度分数，也让你有工具可以有意地变化句式。
怎样发现 comma splice？
看逗号两边的词。如果两边各自都能独立成句，有主语、动词和完整的意思，而且只有一个逗号把它们连在一起，那就是 splice。
The museum closed at five, we arrived at ten past.
两半都是完整的：“The museum closed at five” 和 “We arrived at ten past.”。逗号不能把它们连起来。
有哪四种修正方法？
- 句号。 拆成两个句子：“The museum closed at five. We arrived at ten past.”
- 分号。 两句关系密切时保留为一句：“The museum closed at five; we arrived at ten past.”
- 逗号加并列连词（for, and, nor, but, or, yet, so）：“The museum closed at five, and we arrived at ten past.”
- 从句。 让其中一半依附另一半：“The museum had closed at five by the time we arrived at ten past.”
怎么选取决于你想要的效果。
句号给出两个分开的节拍。分号表示紧密的联系。连词加上精确的关系，从句则告诉读者哪个想法更重要。
例题示范
The storm cut the power at noon, the cafe stayed open, the owner lit candles on every table.
步骤 1，找出分句。 共有三个：“The storm cut the power at noon”、“the cafe stayed open” 和 “the owner lit candles on every table”。每个都有主语和动词。
步骤 2，检验逗号。 两个逗号都连接了完整的句子，所以有两处 splice。
步骤 3，判断关系。 第二和第三个想法属于一起，因为点蜡烛正是咖啡馆继续营业的方式。第一个想法是引发一切的独立事件。
步骤 4，选择修正方式。 第一个分句后用句号，另外两个用连词连接：
The storm cut the power at noon. The cafe stayed open, and the owner lit candles on every table.
步骤 5，朗读。 现在每个句子都能独立站住，“and” 连接的是同一个行动的两个部分。
常见错误
一种很常见的 splice 藏在 “however”、“therefore”、“then” 或 “also” 这类连接副词后面。
错误： The paper was difficult, however I finished every question.
“However” 不是连词，所以即使前面有逗号，它也不能连接两个句子。那个逗号仍然在连接两个完整的句子。
改正方法是在这个副词前面用句号或分号：
The paper was difficult. However, I finished every question.
The paper was difficult; however, I finished every question.
你也可以用真正的连词：“The paper was difficult, but I finished every question.”
自我检测
1. 这是 comma splice 吗？“Although the room was cold, we stayed until the end.”
Show answer
不是。“Although the room was cold” 不能独立成句，因为 “although” 使它依附于其余部分。从句放在句首时，后面用逗号是正确的。
2. 用两种不同方法修正：“Ravi opened the window, the smell of rain came in.”
Show answer
句号：“Ravi opened the window. The smell of rain came in.” 连词：“Ravi opened the window, and the smell of rain came in.” 用从句也可以：“When Ravi opened the window, the smell of rain came in.”
3. 改正这个句子：“The match was cancelled, therefore we went home early.”
Show answer
“Therefore” 不能在逗号之后连接两个句子。写成 “The match was cancelled; therefore, we went home early.” 或 “The match was cancelled, so we went home early.”
接下来学什么
用从句修正最能给你控制力，所以接着学使用从句而不丢失主要意思。如果你想看看几项技能如何一起出现，可以做句子控制练习。
写作修订对比视图能帮你把初稿和改正后的版本并排比较，需要用自己的话重建句子时，摘要筛选与改写工作室也很有用。
有人指出来时，splice 很容易改，自己一个人却很难发现。这类习惯，正是我们的老师在线上一对一 English First Language 补习中帮助你建立的。