1. 定义
状语从句是对主句的谓语动词或整个句子进行修饰的从句，用来说明时间、地点、原因、条件、目的、结果、让步、方式或比较等。
2. 状语从句的结构
主句 + 连词（when/while/because/although/if等）+ 从句
3. 常见连词及其功能分类
类型常用连词功能描述例句
时间状语从句when, while, before, after, since, as soon as表示主句动作发生的时间I was reading a book when he called me.
原因状语从句because, since, as表示主句动作发生的原因I stayed home because it was raining.
条件状语从句if, unless, provided (that), as long as表示主句动作发生的条件If you study hard, you will pass the exam.
让步状语从句although, though, even if, even though表示主句动作成立的让步条件Although it was late, she kept working.
目的状语从句so that, in order that表示主句动作的目的He spoke loudly so that everyone could hear him.
结果状语从句so…that, such…that表示主句动作导致的结果The movie was so funny that everyone laughed loudly.
方式状语从句as, as if, as though表示主句动作的方式He behaves as if he were the boss.
比较状语从句than, as…as, the more…the more表示主句动作与从句的比较关系She is taller than I thought.
4. 不同类型状语从句详解
（1）时间状语从句
描述动作发生的时间，与主句紧密相关。
常用连词：when, while, as, after, before, until, since, as soon as。
例句：
She was cookingwhenI arrived.
Afterhe finished his homework, he went to bed.
（2）原因状语从句
描述动作发生的原因。
常用连词：because, since, as。
例句：
He left earlybecausehe was feeling unwell.
Sinceyou are here, let’s get started.
（3）条件状语从句
描述动作发生的条件，通常用于假设或推断。
常用连词：if, unless, provided (that), as long as。
例句：
Ifit rains tomorrow, we will stay at home.
You cannot succeedunlessyou work hard.
（4）让步状语从句
描述主句成立的对立条件，表达尽管如此的语义。
常用连词：although, though, even though, even if。
例句：
Althoughshe was tired, she continued to study.
I will support youeven ifothers oppose.
（5）目的状语从句
描述主句动作的目的，通常带有“为了”的含义。
常用连词：so that, in order that。
例句：
He works hardso thathis family can live a better life.
（6）结果状语从句
描述主句动作导致的结果。
常用连词：so…that, such…that。
例句：
The soup wasso hot thatI couldn’t eat it.
It wassuch a beautiful day thatwe decided to go for a walk.
（7）方式状语从句
描述动作发生的方式或态度。
常用连词：as, as if, as though。
例句：
He did everythingasI had instructed.
She looksas ifshe has seen a ghost.
（8）比较状语从句
描述动作的比较关系。
常用连词：than, as…as, the more…the more。
例句：
She is smarterthanher brother.
The harder you work,the moreyou will achieve.
5. 状语从句常见错误及注意事项
时态一致性问题
主从句时态应一致或根据意义合理搭配。
错误例句：I will tell you the truth when I will come back.
正确句式：I will tell you the truth when I come back.
连词误用
不同类型的从句需使用正确的连词。
错误例句：He left since it was raining.
正确句式：He left because it was raining.
句子完整性
状语从句不能独立成句，需要依附于主句。
6. 经典练习题
（1）选择合适的连词填空
I will call you _______ I arrive.
(when/while/because)
He went to bed early _______ he was tired.
(if/because/unless)
（2）句子改错
He works hard so he can support his family so that.
正确答案：He works hard so that he can support his family.
（3）翻译练习
如果你明天有时间，请告诉我。
答案：If you have time tomorrow, please let me know.
（4）扩展句子
将以下句子合并为包含状语从句的句子：
She studied very hard. She wanted to pass the exam.
答案：She studied very hard so that she could pass the exam.