狀語(yǔ)從句：

　　時(shí)間狀語(yǔ)從句

　　引導詞：when，while，as，after，before，since，until，as soon as，before，after.

　　When you think you know nothing, then you begin to know something.

　　地點(diǎn)狀語(yǔ)從句

　　where，wherever引導。地點(diǎn)狀語(yǔ)從句與定語(yǔ)從句的區別，where引導定語(yǔ)從句時(shí)，從句前應有一個(gè)表示地點(diǎn)的名詞作先行詞；而狀語(yǔ)從句前則無(wú)需先行詞。

　　原因狀語(yǔ)從句

　　Tom was late because he was badly ill yesterday.

　　引導詞有because, as, since, for，seeing (that), now (that), considering (that)，in that

　　條件狀語(yǔ)從句

　　引導詞：if，unless，on condition that

　　If you want to know how old a woman is, ask her sister-in-law.

　　If引導的真實(shí)條件句，虛擬條件句條件狀語(yǔ)從句中主句使用將來(lái)時(shí)態(tài)，而從句用一般現在時(shí)或現在完成時(shí)。