连词（Conjunction）
在英语语法中，"连词"（Conjunctions）是用来连接词、短语、从句或句子的词语，使语言表达更加流畅和逻辑清晰。连词可以分为几大类，主要功能包括并列、转折、选择、因果、条件等。以下是一些主要类型的连词及其用法示例：
1. 并列连词（Coordinating Conjunctions）
并列连词用于连接两个同等重要的词、短语或句子。最常用的并列连词有：and, but, or, so, yet, for, nor。
- And: She likes coffee and tea. (她喜欢咖啡和茶。)
- But: I want to go out, but I have to finish my homework first. (我想出去，但我得先完成作业。)
- Or: Do you prefer tea or coffee? (你喜欢茶还是咖啡？)
- So: It's raining heavily, so we stayed at home. (雨下得很大，所以我们待在家里。)
- Yet: He is young, yet very experienced. (他很年轻，但经验却很丰富。)
- For: I went to bed early, for I was exhausted. (我早早上床睡觉了，因为我筋疲力尽。)
- Nor: He doesn't like tea, nor does he drink coffee. (他不喜欢茶，也不喝咖啡。)
2. 从属连词（Subordinating Conjunctions）
从属连词用于引导一个从句（通常是名词性从句、形容词性从句或副词性从句），表明该从句与主句之间的逻辑关系。常见的从属连词包括：although, because, if, since, that, unless, until, when, while等。
- Because: I stayed up late because I had to finish a report. (我熬夜了，因为我得完成一份报告。)
- If: If it rains, we'll stay inside. (如果下雨，我们就待在室内。)
- Although: Although she was tired, she kept working. (尽管她很累，但她继续工作。)
- Since: Since you're here, let's have lunch together. (既然你来了，我们一起吃午饭吧。)
- That: I know that she will arrive on time. (我知道她会准时到达。)
- Unless: I won't go unless she invites me. (除非她邀请我，否则我不会去。)
- Until: Wait here until I come back. (在这里等我回来。)
- When: When I saw him, he was reading a book. (当我看到他时，他正在读书。)
- While: While I was studying, she called me. (在我学习的时候，她给我打了电话。)
因果连词
在英语语法中，表达因果关系的连词主要用于连接表示原因和结果的句子或从句。这类连词帮助读者或听者理解事件之间的逻辑联系。以下是几种常用的表达因果关系的连词及其用法示例：
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Because（因为）: 引导原因状语从句，表达直接原因。
- Example: I stayed at home because I was feeling sick. (我待在家里因为我感觉不舒服。)
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Since（既然；因为）: 除了表达时间意义外，也可引导原因状语从句，常用于已知或显而易见的原因。
- Example: Since you're here, let's discuss the project. (既然你在这儿，我们来讨论一下项目吧。)
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As（因为；随着）: 可以引导原因状语从句，表达原因或同时伴随的情况。
- Example: As it was raining, we decided to stay indoors. (因为外面在下雨，我们决定待在室内。)
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Due to（由于）: 虽然不是连词，但作为一个介词短语，它也能表达原因，通常放在名词前或引导整个句子的原因说明。
- Example: The game was canceled due to bad weather. (比赛因为恶劣天气取消了。)
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Owing to（因为）: 类似于'due to'，是一个表达原因的介词短语。
- Example: Owing to his hard work, he passed the exam. (因为他的努力，他通过了考试。)
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Therefore（因此；所以）: 通常用于引出结果，放在句首或句中，连接两个独立的句子。
- Example: She studied hard. Therefore, she got an A on the test. (她学习很努力。因此，她在测试中得了A。)
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Thus（因此；于是）: 和'therefore'类似，也用来表示结果或结论。
- Example: The roads were icy; thus, many accidents occurred. (道路结冰了；因此，发生了多起事故。)
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Consequently（因此；结果）: 强调结果，用于正式文体。
- Example: The company lost a major contract. Consequently, they had to lay off several employees. (公司失去了一项重要合同。结果，他们不得不裁员几位员工。)
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Hence（因此；所以）: 较为正式，用于书面语，指明结果。
- Example: He forgot his password. Hence, he couldn't access his account. (他忘记了密码。因此，他无法访问他的账户。)
