我被学生最常问到的问题之一，就是怎样区分定语从句，宾语从句和状语从句。今天我们对前面几节课的内容做一些提炼，探讨下怎样一眼就能辨别三大从句。
01 概念
3大从句的区别均在于前面两个字：定语、宾语和状语：
知道了这几个概念，这三种从句就很好理解了：
定语从句：作定语/ adj.修饰先行词；
在这里，dog “狗子” 是先行词，即“走在定语从句前面的名词”；定语从句 that shits a lot 其中的 that，指代了前面的 dog，告诉我们这是一条怎样的狗子：拉很多的狗子。
宾语从句：作宾语，放在动词或介词后面；
第一句，宾语从句为普通的陈述句，放在 think 这个动作后面，由连接词 that 引导。
第二句，宾语从句已经改成陈述句语序，原来人讲的话则是一般疑问句 Do you let it go “你丫放不放手” ？该从句放在 depend on 的介词 on 后面，一般疑问句由 whether/ if 引导。
状语从句：作状语，给主句增加信息量。
状语从句，是3大从句中比较好记的一种：有个完整的主句，从句是提供更多信息的，比如上述例句告诉我们他为什么养狗。只要熟悉 （← 戳可查看），几乎一眼就能辨别出状语从句。
02 当堂练习
现在，我们一起看几个句子找找感觉。请判断下列句子是定语从句，宾语从句还是状语从句？
>> 青铜
1. If it is fine tomorrow, I will visit you.
2. I helped an old man who lost his way.
3. I don’t know what I should do next.
>> 白银
4. Mom hates our neighbor whose dog shits at our door.
5. Mom hates our neighbor because his dog shits at our door.
6. Mom asks our neighbor why his dog is so annoying.
>> 黄金
7. Stephen Hillenburg, who created ‘SpongeBob’, died at the age of 57.
8. Stan Lee explained that he used a false name because he wanted to write a serious and great piece of literature someday. He did not want his link with comic books to be known when that happened.
9. A Chinese scientist claims he successfully created the world's first genetically-edited babies.
解析：确切而言，who created 'SpongeBob' 是非限制性定语从句，起补充说明的作用，去掉也不影响主句的完整性；非限制性的特征之一是从句前有逗号，具体参考前几期文章（← 戳可查看）。
解析：这句话摘自VOA慢速英语，沉住气还是可以辨清其中各类从句的：Stan Lee explained 后面的剩余部分，就是“解释”这个动作的宾语从句；这个从句中，又包含 because 引导的原因状语从句，告诉我们斯坦李用假名的原因。
第二句末，还有个短短的、由 when 引导的时间状语从句。
解析：找到动词 claim “声称”，就很容易就定位到后面的宾语从句，只是省略了 that。从句一个完整的句子，有主语 he，谓语 created，宾语 the world's first genetically-edited babies。
>> 王者
10. There will be television chat shows hosted by robots, and cars with pollution monitors that will disable them when they offend.
11. It is not easy to explain why one person is intelligent and another is not，or why one is cooperative and another is competitive.
12. It is also the reason why when we try to describe music with words，all we can do is articulate our reactions to it.
解析：pollution monitor “污染检测仪”在这里作先行词，放在 that 引导的定语从句前面，告诉我们这种检测仪是干什么用的；定语从句中，还包含 when 引导的时间状语从句。
解析：动宾动宾。在动词 explain “解释”后面，紧跟两个 why 引导的宾语从句。这句来自考研真题，不过相对简单。
解析：reason 的定语从句可以由 why 或 for which 引导；该定语从句中又有 when 引导的时间状语从句；
逗号后面的分句主语 all we can do 又出现一个定语从句，只是省略了关系代 词 that。
03 课后巩固
1) Is this park ________ we visited last week?
A. which B. where C. the one
2) Do you remember the park ________ we visited last week?
A. where B. that C. the one
3) This is the park ________ I lost my phone last week.
A. where B. that C. the one
4) His illness will not develop to the point ________ no medicine can cure her.
A. where B. that C. as
5) A computer can only do ________ you have instructed it to do.
A. how B. that C. what
6) No one knows ________ in a million years.
A. what man will look like
B. what will man look like
C. man will look like what
7) I don’t know ________ or not.
A. whether he is at home
B. if he is at home
C. that he is at home
8) If you don’t understand something, you may research, study, and talk to other people ________ you figure it out.
A. because B. until C. when
9) ________ the average age of the population increases, there are more old people to care for.
A. As B. While C. As soon as
10) ________ you may have, you should face the challenge.
A. However a serious problem
B. However serious a problem
C. What a serious problem
获取答案方式
后台回复：三大
「虫虫讲英语」老少咸宜的英语学习号。有时候，语法换一种方式讲，就听懂了。
04 总结
定语从句：作定语/ adj. 修饰先行词；
宾语从句：作宾语，放在动词或介词后；
状语从句：作状语，给主句增加信息量。
如果可以，抽15分钟时间，把前面几节课再看一遍：
定语从句、宾语从句和状语从句，都有自己的关系词或连接词：
对比之下，我们发现这点上比较容易混淆的是定语从句和宾语从句：宾语从句不仅有可以引导一般疑问句的 whether, if，还有引导特殊疑问句的 what 和 how。而定语从句是没有 what 和 how 等引导词的。
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