染雾高中英语语法主从复合句 篇一
从句在句子中起到什么作用？
在英语语法中，从句是一种特殊的句子结构，由一个主句和一个或多个从句组成。从句可以充当主句的主语、宾语、定语或状语，起到丰富句子意义、增强表达能力的作用。
首先，从句可以充当主句的主语。例如：“What he said is true.”（他说的是真的。）从句“what he said”作为主语，起到说明“真实性”的作用。
其次，从句可以充当主句的宾语。例如：“I know that he is coming.”（我知道他要来。）从句“that he is coming”作为宾语，起到说明“我知道的内容”的作用。
此外，从句还可以充当主句的定语。例如：“The book that I bought yesterday is very interesting.”（我昨天买的书非常有趣。）从句“that I bought yesterday”作为定语，起到修饰“书”的作用。
最后，从句还可以充当主句的状语。例如：“She smiled when she saw me.”（她看到我时微笑了。）从句“when she saw me”作为状语，起到说明“微笑的时机”的作用。
总的来说，从句在句子中起到丰富句子意义、增强表达能力的作用。通过从句的运用，我们可以更准确地表达自己的意思，使句子更加清晰、丰富。因此，掌握并灵活运用主从复合句中的从句结构是学好英语语法的重要一步。
高中英语语法主从复合句 篇二
如何正确使用主从复合句中的连接词？
在英语语法中，连接词在主从复合句中起到连接主句和从句的作用。连接词的选择和使用对于句子的意义和表达非常重要。下面是几种常用的连接词及其用法：
首先，当从句作为主句的主语时，我们可以使用连接词“that”。例如：“That he can speak three languages is impressive.”（他能说三种语言令人印象深刻。）
其次，当从句作为主句的宾语时，我们可以使用连接词“if”、“whether”或“that”。例如：“I don't know if/whether he will come.”（我不知道他是否会来。）或“I know that he will come.”（我知道他会来。）
此外，当从句作为主句的定语时，我们可以使用连接词“who”、“which”、“whom”、“whose”、“when”、“where”或“why”。例如：“The girl who is wearing a red dress is my sister.”（穿红裙子的女孩是我妹妹。）
最后，当从句作为主句的状语时，我们可以使用连接词“when”、“where”、“while”、“as”、“since”、“because”、“if”、“although”、“though”、“unless”等。例如：“I will go to the park when the weather is nice.”（天气好的时候我会去公园。）
总的来说，正确使用连接词对于主从复合句的构成和意义非常重要。我们需要根据从句在主句中的作用来选择合适的连接词，并且注意连接词的用法和语法规则。通过正确使用连接词，我们可以使句子更加准确、流畅，并且增强句子的表达能力。因此，掌握和运用主从复合句中的连接词是学好英语语法的关键一步。
高中英语语法主从复合句 篇三
重点内容如下：
①when,while,as引导的时间状语从句
▲as表示“当……的时候”，往往和when/ while通用，但它着重强调主句与从句的动作或事情同时或几乎同时发生。
She came up as I was cooking.(同时)
The runners started as the gun went off.(几乎同时)
▲when(at or during the time that )既可以表示在某一点的时候，又可表示在某一段时间内，主句与从句的动作或事情可以同时发生也可以先后发生。
It was raining when we arrived.(指时间点)
When we were at school, we went to the library every day.(在一段时间内)
When we arrived there,the film had already begun.(先后发生)
▲while意思是“当……的时候”或“在某一段时间里”。主句中的动作或事情在从句中的动作或事情的进展过程中发生，从句中的动词一般要用延续性动词。在when表示a period of time时，两者可以互换。
Please don’t talk so loud while/when others are working.
He fell asleep while/when reading.
Strike while the iron is hot.( 不可用as或when，这里的while意思是“趁……”)
②before状语从句的重点句型
▲……之后……才：It was a long time before I got to sleep .
▲不多久……就：It wasn’t long before he told me about the affair.
▲不等……就：Before I could get in a word, he had measured me.
▲刚……就：He hardly entered the room before he heard the telephone ring.
▲先……再：You can have a few days to think about it before you make your decision.
③since 引导的从句用延续性动词的过去式(包括过去完成时)，则从句的动作已经结束,从句意思是否定的。如果从句的动词是延续性的用完成时态，从句意思是肯定的。
▲He has never been to see me since I was ill.我病愈后，他一直未来看我。(不在生病了)
▲He has never been to see me since I have been ill.我病了，他一直未来看我。
▲I haven’t heard from him since he lived here.
自从他这里搬走，我就没有收到他的信。(不住在这儿了)
▲I know him very well since he has lived here near us.自他住在我们附近以来，我对他很了解。
▲It’s three years since I was in the army.我退伍已三年了。(不在服役了)
▲It’s three years since I have been in the army=It's three years since he joined the army.
我入伍已三年了。
④如果与till与until从句使用的主句是肯定的，则主句中谓语要用延续性动词如果与其使用的主句是否肯定的，则主句中谓语要用短暂性动词。另till从句不可以置于
2.原因状语从句
由下列连词引导：as(由于),because(因为), since(既然),now (that) (既然), considering that(顾及到), seeing that(由于)。
I do it because I like it.因为我喜欢我才干。(because不能与 so连用)
He couldn’t have seen me, because I was not there.他不可能见过我，因为当时我不在那儿。
Seeing (that) quite a few people were absent, we decided to put the meeting off.
由于好些人都没到会，我们决定延期开会
Now that/Since you are all here, let’s try and reach a decision.
既然大家都来了咱们就设法做一个决定吧
As she was ill, she didn’t come to the party.
由于病了，她没来参加晚会。
Considering that they are just beginners, they are doing quite a good job.
考虑到他们才刚刚学做，他们干得算很不错的了。
重点内容如下：
①because语气最强，用于回答why的提问，可与强调词only,just 以及否定词not 连用。但不可以与so连用。如You shouldn’t get angry just because some people speak ill of you.另外注意与not连用时否定的转移。He didn’t do such a thing because he was afraid of his wife.他并不是因为怕他的妻子才做这样的事。
Cf:He didn’t do such a thing,because he was afraid of his wife.因为怕妻子，他没有做这样的事。
because引导的从句可以被强调：
It was because she wanted to study abroad that she entered for TOEFL
②as语气较弱，since语气也较弱，但比as正式一些,所说明的原因比较明显或是已知的事实，多用于口语中，所以不应该强调。常置于句首。
As all the seats were full,he stood there.
Since you are going,I’ll go,too.
③for虽解释为“因为”但只是一个并列连词，它引导的是并列句，不是原因状语从句。
The day was short,for it was December.
3.地点状语从句
由下列连词引导:where,wherever,anywhere,everywhere。
Anywhere he went,he got warm welcome.
The girl takes the doll with her everywhere she goes.
Wuhan lies where the Yangtze and the Han River meet.武汉位于长江和汉水汇合处。
Where there is a will, there is a way.有志者，事竟成。
You’d better make a mark where you have any questions.
哪儿有问题，你最好在哪儿做个记号。(这里where引导的从句不是定语从句)
4.结果状语从句
由下列连词引导：that，so…that，so that(从句中不带情态动词)，such…that，with the result that等。
注意以下几种结构：
①so+adj/adv+that…
②such(a/an+adj)+n+that…
③so+adj+a/an+n+that=such a/an+adj+n+that…
④so many/much/few/little(少)+n+that…
注意以上结构与定语从句so/such…as的区别。
This is such an interesting/so interesting a film that/as everyone wants to see it/(it).
He didn’t plan his time well so that/so he didn’t finish the work in time.
他没把时间计划好，结果没按时完成这项工作。
We left in such a hurry that we forgot to lock the door.
我们走得匆忙，把门都忘了锁了。
The village is so small that it cannot be shown in the map.
这村子太小，所以这地图上没有。
Jenny is such a clever girl that all the teachers like her very much
= Jenny is so clever a girl that all the teachers like her very much
Jenny是如此聪明的女孩，以至老师们都非常喜欢她。
I have had so many falls that I am black and blue all over.
我摔了许多跤，以至于浑身青一块紫一块
He has so few friends that he often feels lonely.
他朋友很少，所以经常感到孤独。
I had so little money then that I couldn’t afford a little present.
我当时囊中羞涩连一份小小礼物都买不起
5.目的状语从句
由下列连词引导：so that,in order that,for fear that等。目的状语从句的谓语动词常与情态动词can, could, may, might, should连用目的状语从句的谓语动词常与情态动词can, could, may, might, should连用。
(so that也可用来引导结果状语从句，但从句中不带情态动词)
Let’s take the front seats (so) that we may see more clearly.
我们坐前排吧，这样我们看得更清楚些。
School was closed early in order that the children might go home ahead of the storm.
早点儿放学是为了让孩子们在暴风雨到来之前回家。
He took the name down for fear that he should forget it.
他把名字写下省得忘了。(该从句中一般用情态动词should+动词原形，或省略should)
Better take more clothes in case the weather is cold.
最好多带些衣服以防天气会冷。
注意：so that引导的目的状语从句只能放在主句之后，in order that 引导的目的状语从句可以放在主句之前或之后。
6.条件状语从句
分为真实条件句和非真实条件句(用在虚拟语气中)。
表示条件的状语从句可以由if(如果),unless(除非), in case(万一), so /as long as(只要), as/ so far as(就……而言), on condition that(条件是……)suppose(假设)supposing(假设)(仅用在问句中)
等词或词组引导。一般情况下当主句是将来时的时候，从句要用一般现在时。
As/So long as we don’t lose heart, we’ll find a way to overcome the difficulty.
只要我们不灰心，我们就能找到克服困难的方法。
Send us a message in case you have any difficulty.万一你有什么困难，请给我们一个信儿。
If you leave at 6 o’clock tomorrow morning, you’d better get to bed now.
如果你明早6点钟走，你最好现在就上床。
We’ll let you use the room on condition that you keep it clean and tidy.
只要你能保持整洁，我们可以让你使用这个房间。
As/So far as I know, he is an expert on DNA.据我所知，他是一个DNA专家。
He’ll accept the job unless the salary is too low/ if the salary is not too low.
他会接受这项工作的，除非薪水太少/如果薪水不太少的话。
Suppose/Supposing we can’t get enough food, what shall we do?
假设我们弄不到足够的食物，那我们怎么办?
