1．時間狀語從句：
as（當……的時候）,as soon as（一……就……）,
As / When I came home,I met an old schoolmate of mine.我回家的時候遇到了我的一位老同學.
I’ll ring you up as soon as I get an answer from him.我一有他的答覆就給你打電話.
2．原因狀語從句
表示原因的狀語從句可以由as（由於）
As she was ill,she didn’t come to the party.由於病了,她沒來參加晚會.
3．條件狀語從句
so /as long as（只要）,as/ so far as（就……而言）,
As/So long as we don’t lose heart,we’ll find a way to overcome the difficulty.只要我們不灰心,我們就能找到克服困難的方法.
As/So far as I know,he is an expert on DNA.據我所知,他是一個DNA專家.
4．方式狀語從句
方式狀語從句常由as（與……一樣）,as if（彷彿）,as though（彷彿）等詞引導：
Do in Rome as the Romans do.入鄉隨俗.
Leave things as they are.讓一切順其自然.
She stood at the door as if (=as though) she were waiting for someone.她站在門口,彷彿在等人似的.（由as if或 as though引導的從句中可用虛擬語氣）
5．比較狀語從句
as（與……一樣）
Our country is as big as the whole of Europe.我們的國家同整個歐洲一樣大.
The result was not as/so good as I had expected.結果不如我預料的那麼好.
6．讓步狀語從句
連詞as也可以引導讓步狀語從句,但從句中要用特殊語序.如：
Young as he is,he knows a lot=Though he is young 或Young though he is,he….
他雖然年輕,但懂得很多.(though 也有這種用法,可以替換as,但although沒有這種用法)
though還可以用作副詞,放在句末.如：
It was hard work; I enjoyed it,though.=It was hard work,but I enjoyed it.那工作很苦,但是我喜歡幹.
1．時間狀語從句：
as（當……的時候）,as soon as（一……就……）,
As / When I came home,I met an old schoolmate of mine.我回家的時候遇到了我的一位老同學.
I’ll ring you up as soon as I get an answer from him.我一有他的答覆就給你打電話.
2．原因狀語從句
表示原因的狀語從句可以由as（由於）
As she was ill,she didn’t come to the party.由於病了,她沒來參加晚會.
3．條件狀語從句
so /as long as（只要）,as/ so far as（就……而言）,
As/So long as we don’t lose heart,we’ll find a way to overcome the difficulty.只要我們不灰心,我們就能找到克服困難的方法.
As/So far as I know,he is an expert on DNA.據我所知,他是一個DNA專家.
4．方式狀語從句
方式狀語從句常由as（與……一樣）,as if（彷彿）,as though（彷彿）等詞引導：
Do in Rome as the Romans do.入鄉隨俗.
Leave things as they are.讓一切順其自然.
She stood at the door as if (=as though) she were waiting for someone.她站在門口,彷彿在等人似的.（由as if或 as though引導的從句中可用虛擬語氣）
5．比較狀語從句
as（與……一樣）
Our country is as big as the whole of Europe.我們的國家同整個歐洲一樣大.
The result was not as/so good as I had expected.結果不如我預料的那麼好.
6．讓步狀語從句
連詞as也可以引導讓步狀語從句,但從句中要用特殊語序.如：
Young as he is,he knows a lot=Though he is young 或Young though he is,he….
他雖然年輕,但懂得很多.(though 也有這種用法,可以替換as,但although沒有這種用法)
though還可以用作副詞,放在句末.如：
It was hard work; I enjoyed it,though.=It was hard work,but I enjoyed it.那工作很苦,但是我喜歡幹.