⑤原因状语从句，引导词有：because 因为；as 因为，由于；since 既然，因为。
如：Because the traffic is so busy, she failed to arrive at the station on time.
因为路上交通太拥挤，她没能准时赶到车站。
Asyou're tired, let's rest. 因为你累了，我们休息吧。
Sinceyou're here, let's begin. 既然你来了，我们开始吧。
⑥让步状语一般指情况的对比，表示“退一步说”的意思。
A. 让步状语从句的连词有：while虽然；even if= even though即使；although = though尽管、即使，前者比较正式，后者经常用于口语，不可以和but连用，但可以同still或yet连用。
如：While I understand your opinion, I cannot agree with you.
虽然我理解你的观点，但我不能同意你。
We won't be discouragedeven if we fail ten times.
即使我们失败了十次，我们也不会气馁。
Although/Though he was tired, he still kept on working.
尽管他已经很累了，依然继续努力工作。
B.表选择，whether不管……，无论……。
如：You'll have to attend the ceremony whether you're free or busy.
不管你忙或不忙，你都要参加这个典礼。
Whether it rains or not, we'll go. 无论下不下雨，我们都会去。
C.no matter 不管……，无论…… + 疑问词。只能用于句首。相当于whatever不管什么，whoever无论是谁，whenever无论何时，wherever不管什么地方。
如：No matter what happened, he would not mind.
不管发生什么他都不会介意。
No matter who you are, you must keep the law.
= Whoever you are, you must keep the law. 不管你是谁都必须遵守法律。
⑦比较状语从句，引导词有：as...as... 和……一样……的；not so /as...as... 不如……的，比不上……的；more...than 比……更……；no more...than... 没有……更……的；the more...the more... 越……就越……的。
A.as + ...形容词/副词... + as + 从句
如：He knows as much as I do. 他知道的和我一样多。
You should speak English as often as you can. 你应该尽可能多地说英语。
B.not so(/as) + ...形容词/副词... + as + 从句
如：She doesn't work so hard as you do. 她不像你那么努力工作。
The task is not as easy as we thought. 这项任务不是我们想的那么容易的。
C....形容词(副词)比较级... + than + 从句
如：The situation was worse than it used to. 情况比过去更糟了。
You look much better than you did weeks ago.
你看起来比几周前好多了。
There were more customers in the store than I expected.
店里的顾客比我预期的要多。
D.no + 形容词(副词)比较级... + than + 从句
如：I think there is no prettier girl than she is. 我认为她是最漂亮的女孩。
E.The + 形容词或副词比较级 + 从句，the + 形容词或副词比较级 + 从句
如：The moreyou read, the fasteryou will be. 你阅读量越大，你就越快。
⑧方式状语，由as，as if 引导。
如：Do as I told youjust now. 照我刚才跟你说的去做。
She treats him as if he were her own son. 她把他看成是自己的亲生儿子一样。
