状语从句

状语通常表达如下内容： 时间、地点、原因、结果、目的、让步、条件、比较、方式、 伴随、程度、频率。(粗体的可以做状语从句)

  • 状语从句在句子中的位置非常灵活，其位置主要取决于与主句的逻辑关系及强调重点

    • 状语从句放在句首时，强调状语，引导背景，必须用逗号和主句分开

    • 状语从句放在句尾时，最自然、常用，作为补充信息，逗号可加可不加，语法上均正确，具体是否加主要取决于从句的必要性和主句的紧密程度。

      • 更精确的结论：当是让步状语从句时，建议加逗号；时间/条件/原因 状语从句通常不加逗号。

    • 状语从句放在句中，插入语形式，前后都用逗号与主句隔开。

  • I always get up early to make lunch.我总是早起做早餐。

    • 状语1：always:频率,副词,修饰谓语动词get up.

    • 状语2：early:时间,副词,修饰谓语动词get up.

    • 状语3：to make lunch: 动词不定式短语,在句中做目的状语.

  • He never runs with a dog at home.

    • never:频率

    • with a dog:伴随

    • at home:地点

以上是单词或短语来充当状语；当状语由句子充当时，就是状语从句.一共有9类可以充当状语从句。如下：

  1. 时间状语从句

    • 引导词:when, while, as, before, after, since, until, as soon as, the day, the moment, the minute, the second, every time, each time等.

    • When I get home, I will call you.当我到家时，我就给你打电话。

    • I didn't realize it until I became a father.直到我成为一个父亲我才意识到这个。

  2. 地点状语从句

    • 引导词：where, wherever, anywhere, everywhere等.

    • Air is heavily polluted where there are factories.有工厂的地方空气污染就严重。

    • You should put the book where it was.你应该把书放回原来的地方。

  3. 原因状语从句

    • 引导词：because, since, as, now that等

    • They don't like me because I am ugly.他们不喜欢我，因为我长的丑。

    • 为什么没有for，因为for是并列连词，他链接前后两部分为并列句，即前后两部分语法地位相同，而原因状语从句，是从属关系。

  4. 结果状语从句
    • 引导词：so...that..., such...that...等。

      • so+形容词; such+名词; 如此...以至于...

    • He got up so early that he caught the first bus.他很早起床以至于赶上了第一班公共汽车。

    • It's such a good chance that we mustn't miss it.这是一个好机会，千万不能错过它。

  5. 目的状语从句

    • 引导词：so that, in order that, in came等。

    • He raised his voice in case we couldn't hear him.他提高了声音，以防我们听不到。

    • I eat a lot of food so that I can get fat. 我吃很多食物以便于 能够长胖。

  6. 让步状语从句
    • 引导词：though, although, even if, even though, whatever, whoever, wherever, whenever, however, whichever, "no matter+特殊疑问词"等

      • though, although虽然

      • even if, even thgouh即使

      • whatever, whoever ...(无论...)

      • no matter+特殊疑问词 语义上相等于 上一组

    • Though I am tired,I still want to work.虽然我很累，但依旧想工作。

      • though 和 but 不能同时出现，but叫并列连词，前后句语法地位相同，而这里though引导的这个叫从句，后面I引导的这叫主语，这是一个主从句。

    • Wherever you go, I will follow you.无论你去哪，我都跟着你。

      • No matter where you go, I will follow you.

  7. 条件状语从句

    • 引导词：if, unless, in case, as long as等。

    • We'll start our project if he agrees.如果他同意，我们将开始我们的项目。

    • You will succeed as long as you work hard.你会成功,只要你努力工作。

  8. 比较状语从句

    • 引导词：than，as等.

    • His rudeness is more than I can bear.他的无礼已经超过了我所能忍受的限度。

    • The teacher is as tall as I am.老师像我一样高。

      • The teacher is as tall as I.老师像我一样高。

      • The teacher is as tall as me.老师像我一样高。

      • than, as不但可以作为连词来连接比较状语从句，而且还可以当介词

  9. 方式状语从句

    • 引导词：as, as if, the way等.

    • When in Rome, do as the Romans do.入乡随俗

状语从句的省略

状语从句主语的省略

当状语从句的主语是虚主语it，或者状语从句的主语和主句主语相同时，则从句可省略。其方法是：先把从句的主语和be动词去掉,然后把剩余动词变成分词形式：主动关系用现在分词，被动关系用过去分词:

  • If it is possible, you can come to my house.

    • If possible, you can come to my house.

  • When she was cooking,she heard someone call.

    • When cooking,she heard someone call.

  • I was surprised when I came into the classroom.

    • I was surprised when caming into the classroom.

  • The elephant is happy, though it is left in the zoo.

    • The elephant is happy, though left in the zoo.

  • Because he is to work, he must get up early.

    • Because to work, he must get up early.

  • Before I sleep, I will finish my homework.
    • Before sleepping, I will finish my homework.

      • 这里的sleepping是动名词，因为Before这里充当介词了

      • Before/After加句子时是连词，不加句子是介词，介词后面要跟名词。

  • After he was taken home, the boy cried.

    • After taken home, the boy cried. X

    • After being taken home, the boy cried.

      • Before/After加句子时是连词，不加句子是介词，介词后面要跟名词。

状语从句引导词的省略

状语从句主语省略之后，在不影响句意的情况下，引导词也可以省略。(引导词省略的前提是状语从句的主语省略)

  • When I sang, I felt happy.

    • When singing, I felt happy.

    • singing, I felt happy.

    • 现在分词作状语

  • After I ate dinner, I went for a walk.

    • After eating dinner, I went for a walk.

    • Eating dinner, I went for a walk. X

      • 句意改变了

      • Having eaten dinner, I went for a walk.

        • 句意符合，正确

  • Though it is left in the zoo, the elephant is happy.

    • Though left in the zoo, the elephant is happy.

    • Left in the zoo, the elephant is happy.

    • 过去分词作状语

  • Becase he is to work, he must get up early.

    • Becase to work, he must get up early.

    • To work, he must get up early.

    • 动词不定式作状语

  • When he was at scholl, he studied English.

    • When at scholl, he studied English.

    • At scholl, he studied English.

    • 介词短语作状语

  • When I am happy, I will sing.

    • When happy, I will sing.

    • Happy, I will sing.

    • 形容词作状语

注意:

状语从句省略的第一步，先把从句主语和be动词省略，倘若只省略主语，不省略be动词会如何？

When he was at school, he studied English.
When was at school, he studied English. X
When being at school, he studied English.
Being at school, he studied English.(原本的介词短语做状语变成了现在分词做状语)

结论:状语从句省略主语，不省略be动词语法上亦可。但是通常不自然不推荐的写法。一般可以省略的话还是将be动词和主语一起省略。

if真实条件状语从句

如果假设的条件有可能发生，则为真实条件句。
如果假设的条件通常不可能发生，则为虚拟条件句。
If I'm hungry,I will sleep.
If it will rain tomorrow, I will have water to drink. X
If it rains tomorrow, I will have water to drink.

if真实条件句要遵循"主将从现"的原则。

主将从现

主语

if条件从句

一般将来时

一般现在时

将来进行时

现在进行时

将来完成时

现在完成时

情态动词

现在完成进行时

祈使句

情态动词

不用死记硬背，你只需要知道你想要表达的含义即可.从含义出发.

I will be angry, if you don't come.
If it doesn't rain tomorrow,I can go to the park.
If you don't finish your homework, do it now.
If you are eating dinner, I will call you later.
If you can help me, I will be very happy.
If you have finished your homework,you can do mine.

if真实条件状语从句和简单句的转换

  1. 转换为祈使句，and/or+简单句

  • If you study hard, you'll pass the exam.

    • Study hard, and you'll pass the exam.

  • If you don't hurry up, you'll be late.

    • Hurry up, or you'll be late.

    • Hurry up, and you'll arrive on time.

  1. 借助介词with或without来转换

  • if you help me, I'll finish my job soon.

    • With your help, I'll finish my job soon.

    • Without your help, I won't finish my job soon.

  • If there is no water, fish may die.

    • Fish may die without water.

注意：

在if真实条件状语从句中，当主句是一般将来时时，不使用be going to do的结构。因为它意为 打算去做某事 ,不存在前提条件，是已经计划好的时候。

I'll help you with your English if I am free tomorrow.