because vs so

一句话判据：数一数句子里出现几个因果连词——because 和 so 只能留一个。because 是从属连词，引导原因从句、可放在主句前；so 是并列连词，只能夹在两个分句中间，表示”因此”。

一、对照表

| 维度 | because | so | | 词性 | 从属连词 | 并列连词 | | 引导 | 原因状语从句 | 结果分句（构成并列句） | | 位置 | 从句可在主句之前或之后 | 只能位于两个分句之间 | | 能否互相套用 | ✗ | ✗ | | 回答 why | ✓ | ✗ | | 其他功能 | 可引导表语从句、可用于强调句；because of + 名词/代词/动名词/what 从句 | 只表结果，不表目的（表目的用 so that + 情态动词） |

二、例句对照

because： - Because he is very busy, he can’t come.（因为他很忙，不能来。） - It is because he is too foolish.（那是因为他太蠢了。） - “Why didn’t he come?” “Because he was ill.“（”他为什么没来？”“因为他病了。”）

so： - I was tired, so I went to bed earlier.（我累了，所以早点睡了。） - There were no buses, so I came by bicycle.（没有公共汽车，所以我就骑自行车来了。） - It’s very cold, so wear a heavy coat.（外边很冷，因此穿一件厚大衣吧。）

三、易错陷阱

• 母语干扰点：汉语”因为……所以……”可以同现，英语不行 → ✗ Because he is very busy, so he can’t come. → ✓ 去掉 because（变并列句）或去掉 so（变主从复合句）
• 写作续写里的高频错：✗ Because that was a difficult question, so I answered it last. → ✓ That was a difficult question, so I answered it last.／Because that was a difficult question, I answered it last.
• because of 后接什么：✗ I can’t do the work because of I’m ill. → ✓ I can’t do the work because I’m ill.／because of my illness.（because of 是复合介词，只能接名词、代词、动名词或 what 从句，不能接 that 从句或无引导词的句子）
• because of 短语别当表语：✗ His absence was because of the rain. → ✓ His absence was due to the rain.／He was absent because of the rain.（主语是代词时才可说 It is just because of money.）
• not…because… 的歧义：I didn’t go because I was afraid. 既可理解为”我没有去是因为怕”，也可理解为”我不是因为怕才去”；要表后者，可在 because 前加逗号，或借助 just：You shouldn’t get angry just because some people speak ill of you.

四、记忆口诀

因为所以二者留一，because 从句 so 并列；写成 “because…so…” 就是中式英语。

五、相关链接

连词、状语从句、高考语法高频考点与命题陷阱、语法在写作中的升级用法

六、来源

• 语法体系/英语语法网专栏/状语从句/00654-使用because的五注意.md
• 语法体系/英语语法网专栏/连词用法/04996-并列连词so的用法说明.md
• 语法体系/英语语法网专栏/连词用法/03406-表因果关系的并列连词.md
• 语法体系/英语语法网专栏/连词用法/05005-because, since, as与for用法辨析.md