连词

连词是连接词、短语、分句或句子的虚词，分并列连词（连接对等成分）与从属连词（引导从句）两大类。

一、核心规则

1. 并列连词四类关系：并列/递进（and, both…and, not only…but also, neither…nor）、转折（but, yet, while, whereas）、选择（or, either…or, otherwise）、因果（for, so, therefore）。
2. 关联并列连词连接相同性质的成分，有时后一成分可省略与前一成分相同的词：He spoke with both kindness and understanding.
3. 关联并列连词作主语时的主谓一致：both…and 连接主语谓语用复数（Both she and Sophia were pleased.）；either…or, neither…nor, not only…but also 连接主语时谓语通常与靠近的主语一致（Either you or I am wrong.；Not only you but also he has to leave.）。参见 就近原则 vs 就远原则。
4. or 的五类用法：① 表选择（tea or coffee）；② 表否定条件”否则”（Hurry up, or you’ll be late.）；③ 表”要不就是”（He must be joking, or else he’s mad.）；④ 用于否定句代替 and（They didn’t sing or dance. = 既没唱歌也没跳舞）；⑤ 习语（more or less, one or two）。
5. 从属连词按从句类型分工：引导名词性从句用 that, whether, if（见 名词性从句、宾语从句、主语从句、表语从句、同位语从句）；引导状语从句用 when/while/as/because/since/if/unless/although/so that 等（见 状语从句）；引导定语从句的是关系代词与关系副词（见 定语从句）。
6. because / since / as / for 的判据：because 语气最强，表直接原因，可回答 why、引导表语从句、用于强调句；since/as 表已知原因，since 语气稍强且更正式，通常放主句前，since 还可用于省略句（Since so, I have nothing to say.）；for 是并列连词，只能放主句之后，既可表因果（可与 because 换用），也可只对前句作解释推断（不能换 because）。
7. because of 是短语介词，后接名词或动名词，不能接从句；because 后接从句。
8. 不能”连词 + 连词”叠用：although 与 but 不同现、because 与 so 不同现（见 although vs though vs as、because vs so）。

二、结构与公式

• 并列：A + 并列连词 + B（A、B 须同性质：词/短语/分句）
• 关联并列：both A and B（谓复）｜either A or B（谓随 B）｜neither A nor B（谓随 B）｜not only A but also B（谓随 B）
• 从属：主句 + 从属连词 + 从句 ／ 从属连词 + 从句, 主句
• 原因：because + 从句（直接原因）｜since/as + 从句（已知原因）｜for + 分句（补充说明，前置逗号，只放后）
• 选择与否则：or（选择）｜祈使句 + or + 陈述句（否则）｜祈使句 + and + 陈述句（就）

三、典型例句

1. Both she and Sophia were pleased with the girl.（她和索菲娅都喜欢这姑娘。）——both…and 连接主语，谓语用复数。
2. Either you or I am wrong.（不是你错，就是我错。）——谓语与靠近的主语一致。
3. Neither he nor I know the answer.（他和我都不知道答案。）——neither…nor 的谓语就近。
4. Not only men but also women were chosen.（选中的不仅有男的也有女的。）
5. Hurry up, or you’ll be late for school.（赶快，否则你上学就要迟到了。）——or 表”否则”。
6. He must be joking, or else he’s mad.（他一定在说笑话，要不就是疯了。）
7. They didn’t sing or dance.（他们既没有唱歌也没有跳舞。）——否定句中 or 代替 and。
8. It must have rained last night, for the ground is wet this morning.（昨晚一定下过雨，你看今天早上地面是湿的。）——for 表推断，不能用 because 替换。
9. As you weren’t there, I left a message.（由于你不在那儿，我留了个口信。）——as 引导已知原因，置于主句前。

四、易错点

• ✗ Either of the two answers are correct. → ✓ Either of the two answers is correct.——either/neither of 作主语谓语用单数。
• ✗ Although he was tired, but he kept working. → ✓ Although he was tired, he kept working.——although 与 but 不能同现。
• ✗ Because it was raining, so we stayed at home. → ✓ Because it was raining, we stayed at home.——because 与 so 不能同现。
• ✗ He didn’t come because he was ill. 与事实不符时应用 He didn't come **because** he was ill. 注意否定转移：He didn't come because he was ill. 常理解为”他来了，但不是因为生病”——歧义句要改写。
• ✗ Because of he was late, we missed the train. → ✓ Because of his being late, we missed the train. / Because he was late, we missed the train.——because of 后不能接从句。
• ✗ Both of them is my friend. → ✓ Both of them are my friends.——both 表复数概念。

五、高考考点

1. 语法填空：无提示词的连词空常考并列与从属的区分，如 ___ he was ill, he still came 填 Though/Although 而不填 But。
2. 短文改错：although…but、because…so 叠用是最高频改点；and/or 在否定句中误用；主谓一致随连词变化。
3. 单项选择：either…or 与 neither…nor 的就近一致、or 表”否则”与 and 表”就”的祈使句结构。
4. 写作：并列连词用 and/but 起句过多会使文章单调，应换用 Moreover, However, Therefore 等连接副词；注意连接副词是副词不是连词，须用分号或句号隔开。

六、对比与延伸

介词、状语从句、名词性从句、定语从句、主谓一致、就近原则 vs 就远原则、because vs so、although vs though vs as

七、来源

• 语法体系/英语语法网专栏/连词用法/00152-并列连词词组的用法.md
• 语法体系/英语语法网专栏/连词用法/00155-because, since, as, for的用法区别.md
• 语法体系/英语语法网专栏/连词用法/00879-or的用法归纳.md