我們知道,When引導(dǎo)的時(shí)間狀語(yǔ)從句,表示當(dāng)一個(gè)動(dòng)作發(fā)生時(shí),另一個(gè)動(dòng)作同時(shí)發(fā)生.
所以依據(jù)when時(shí)間狀語(yǔ)從句的定義,應(yīng)該主,從句中要有一個(gè)為進(jìn)行時(shí),或兩個(gè)都為進(jìn)行時(shí)（類似有：while,as,)如下例所示.
When I saw her, she was typing a letter.
When/(while) I was doing my homework, my mother was doing housework.
賓語(yǔ)從句-時(shí)態(tài)
1·主句用一般現(xiàn)在時(shí),從句可用任意時(shí)態(tài).
2·主句用過去時(shí),從句用過去某個(gè)時(shí)態(tài).
3·主句用過去時(shí),從句是真理時(shí),只用一般現(xiàn)在時(shí).
賓語(yǔ)從句-連接詞
1．連詞that：只起連接作用,在從句中不作句子成分,也無(wú)詞匯意義,在口語(yǔ)中或非正式文體中常被省略.
He knew（that）he should work hard．
2．連詞whether或if：它們起連接作用,在從句中不作句子成分,作“是否”解,口語(yǔ)中多用if.
Do you know whether he will ride here at 8 tomorrow morning?
3．連接代詞who,whom ,whose,what, which：它們起連接作用,作句子成分,各有其自己的意義.
The teacher asked the new student which class he was in?（which引導(dǎo)賓語(yǔ)從句,在從句中作定語(yǔ),修飾class,意為“哪個(gè)”.）
4．連接副詞when,where, why,how：起連接作用,分別作時(shí)間、地點(diǎn)、原因、方式狀語(yǔ),各有其自己的意義.
I wonder where he got so much money．對(duì)他從哪里弄到那么多錢我感到疑惑.（where在從句中作地點(diǎn)狀語(yǔ),修飾got,意為“哪里；什么地方”.