英语语法：并列举和复合句（三）原因状语从句引导原因状语从句的从属连词有：because（因为）, as（由于）, since（既然）, now(that)（既然）, when（既然）, seeing (that) （由于，鉴于）, considering (that)（考虑到）, given (that) （考虑到）等，每个连词的含义不尽相同。
主要的有because, for, in that, for the reason that; as, seeing (that), seeing as; since; now (that); considering (that)等：The woolly shrank because it was washed badly. 毛衣因为洗涤的方法不好而缩水。
I can’t get to sleep because of the n oise outside. 由于外面声音嘈杂我睡不着。
Since [As] we’ve no money, we can’t buy it. 由于我们没钱，我们不能购买它。
Seeing that it’s raining, we’d better stay indoors. 既然外边在下雨，我们最好待在室内。
Now that you are here, you’d better stay. 你既然来了，最好还是留下吧(既来之，则安之)。
【注】除以上提到的大家比较熟悉的引导原因状语从句的从属连词外，when有时也可引导原因状语从句(when表示“既然”)些辅助性的补充说明，for引导的并列句只能放于主句之后并且必须用逗号将其与主句隔开。
He could not have seen me, for I was not there.他不可能见过我，因为我不在那里。
He seldom goes out now, for he is very old.他难得出门了，因为他年事已高。
注意：①in view of the fact that可用as/since/seeing that来表示，但不能用because：As/Since/Seeing that you are here，you may as well give me a hand.既然你在这里，你就帮我个忙吧。
As/Since/Seeing that Tom knows French, he'd better do the talking.既然汤姆懂法语，最好让他来谈。
②在as/since/seeing that意指以前共知的或共知的陈述时，可用if来代替：As/Since/Seeing/If you don't like Bill。
why did you invite him?既然/如果你不喜欢比尔，你为什么邀请了他？（四）目的状语从句目的状语的从句可以由that, so that, in order that, lest, for fear that, in case等词引导。
1.so that, in order that引导的状语从句中常用情态动词；in order that较为正式，引导的状语从句可位于主句前/后；而so that引导的状语从句只能位于主句之后。
She worked hard so that everything would be ready by 5 o'clock.她努力工作，以便在五点前是一切都就绪。
I get up early in order that I can catch the early bus.= In order that I can catch the early bus, I get up early.2. for fear that, in case引导状语从句时，for fear that表示“害怕，担心”某事会发生；in case表示“以防（万一）”出现某种情况。
He was worried for fear（that）the child might hurt himself.他很担心孩子会伤了自己。
Take your raincoat in case it rains.（五）结果状语从句1.结果状语的从句可以由so… that，so that，such…that引导。
=Mike is so honest a worker that we all believe in him.= So honest a worker Mike is that we all believe in him.= such an honest worker Mike is that we all believe in him.It is such fine weather that we all want to go to the park.He earned so little money that he couldn’t support his family.除结果状语从句以外，too…to…，enough to…，so…as to…等结构同样表示结果。
He didn’t get up early enough to catch the bus.= He get up too late to catch the bus.= He get up so late as to miss the bus.（六）条件状语从句引导条件状语从句的从属连词有：if（如果，假设），unless（除非，若不，除非在……的时候），on condition(that)...（在……条件下），suppose/supposing（如果，假设），provided that（假如，除非，以……为条件），so/as long as（只要），in case （如果）主句用一般将来时，if或unless引导的条件状语从句用一般现在时。
【注：在条件状语从句中，绝大数情况下some要变为any。
】You will fail to arrive there in time unless you start earlier.如果你不早点动身，你就不能及时赶到那儿。
I can tell you the truth on condition that you promise to keep a secret.我可以告诉你真相，条件是你答应保密。
Supposing it rains, shall we continue the sports meeting?倘若下雨，我们的运动会还要继续举行吗?He won't be against us in the meeting provided that we ask for his advice in advance.如果我们提前征求一下他的意见，他就不会在会上反对我们。
从上述例句可以看出if, unless, on condition (that), supposing, provided等词引导的条件状语从句，主从句条件关系分明，结构清晰。
但有些句子，虽没有含条件关系的连词，却也隐含着条件关系，这些句子常用一些词，如but for, without等引出一个介词结构来表示条件，条件应该是虚拟的，或与事实相反的假设。
如：but for若非，要不是But for the rain, we should have a pleasant journey.要不是下雨，我们的旅行肯定会很愉快。
But for your help, we should not have finished in time.要不是你帮忙，我们肯定不能及时完成任务经典语句：If it doesn't rain tomorrow, we will go to the zoo.If you open the door，i will come in.（七）让步状语从句引导让步状语从句的连词主要有以下这些：⑴though, although表示“虽然，纵然”之意这两个连词意思大致相同，在一般情况下可以互换使用。
在口语中，though较常使用，although比though正式，二者都可与yet, still或never，the less连用，但不能与but连用。
Though I believe it, yet I must consider.尽管我相信这一点，但我还得考虑考虑。
Although/Though he was exhausted,(still) he kept on working.虽然他已经精疲力竭了，但仍然继续工作。
Although/Though he is very old,(yet) he is quite strong.他虽然年纪大了，身体还很健壮。
注意：although引导的让步状语从句位于主句之前的情况较多，though引导的让步状语从句可位于主句之前或主句之后。
例如：She passed the examination though she had not studied very hard.她虽然不用功学习，考试却及格了。
⑵as（though）as引导的让步状语从句必须以部分倒装的形式出现，被倒装的部分可以是表语、状语或动词原形，though也可用于这样的结构中，但although不可以这样用。
Object as/though you may, I’ll go.(=Though/Although you may object, I’ll go.)纵使你反对，我也要去。
Hard as/ though he works, he makes little progress. (=Though he works hard, he makes little progress.）尽管他学习很努力，但几乎没取得什么进步。
Child as/though he was, he knew what was the right thing to do.=Though he was a child, ……虽然他是一个孩子，但他知道该做什么。
Fas t as you read, you can’t finish the book so soon.纵然你读得快，你也不能这么快读完这本书。
（3）whether...or...（不管…还是…）；疑问词+-ever与no matter+疑问词（不管…；无论）Whether you believe it or not, it is true.Whatever(=no matter what) you say, he won’t believe you.Whoever(=no matter who) you are, you must obey the rules.注意：Whatever，Whoever，Whomever，Whichever还可以引导名词性从句。