when引導(dǎo)的時(shí)間狀語(yǔ)從句的用法
when引導(dǎo)的時(shí)間狀語(yǔ)從句可以接一段時(shí)間或者一個(gè)具體的時(shí)間點(diǎn)，從句的謂語(yǔ)動(dòng)詞可以是延續(xù)性的動(dòng)詞，也可以是瞬時(shí)動(dòng)詞。when表示“當(dāng)…時(shí)”“在…時(shí)”，或"就在那時(shí)"。
【1】在過(guò)去，when從句和主句的動(dòng)作先后發(fā)生
解釋：表示在過(guò)去，主句和從句包含的動(dòng)作先后發(fā)生了，或者主句或從句的動(dòng)作先發(fā)生。
句子結(jié)構(gòu)：when從句和主句都用過(guò)去式。
例句：
When I lived in the countryside, I used to carry some water for him.
當(dāng)住在農(nóng)村時(shí)，我常常為他擔(dān)水。
When they began to talk about him he pricked his ears.
當(dāng)他們開始議論到他時(shí)，他豎起了耳朵。
說(shuō)明：
主句過(guò)去式常用 was(were) about to， was (were) on the point 等詞組。如：
We were about to leave when he came in.
我們就要離開，就在那時(shí)他進(jìn)來(lái)了。
We were about to start when it began to rain.
我們剛要出發(fā)就開始下雨了。
He was on the point of leaving when someone knocked at the door.
他剛要走就有人敲門。
【2】在過(guò)去，主句動(dòng)作發(fā)生時(shí)，when從句動(dòng)作正進(jìn)行
解釋：表示在過(guò)去，當(dāng)主句的包含動(dòng)作發(fā)生時(shí)，從句的動(dòng)作在當(dāng)時(shí)也正在進(jìn)行。此類句子主句動(dòng)詞為瞬間性，從句動(dòng)詞為延續(xù)性。
句子結(jié)構(gòu)：when從句用過(guò)去進(jìn)行時(shí)，主句用過(guò)去式。
例句：
When rolling down the hill, he snatched at a rock.
在向山下滾的過(guò)程中，他一把抓住了一塊巖石。
When running, he stumbled me.
跑動(dòng)之中他把我絆倒了。
When I was having breakfast,my dad went out of home.
當(dāng)我吃早飯的時(shí)候，我爸爸就出門了。
【3】在過(guò)去，when從句動(dòng)作發(fā)生時(shí)，主句動(dòng)作正進(jìn)行
解釋：表示在過(guò)去，當(dāng)從句的動(dòng)作發(fā)生時(shí)，主句的動(dòng)作在當(dāng)時(shí)也正在進(jìn)行。此類句子主句動(dòng)詞為延續(xù)性，從句動(dòng)詞為瞬間性。
句子結(jié)構(gòu)：when從句用過(guò)去式，主句用過(guò)去進(jìn)行時(shí)。
例句：
When I got up,my mum was serving breakfast.
當(dāng)我起床的時(shí)候，我媽媽正在給我準(zhǔn)備早餐。
When she came in, I was eating.
她進(jìn)來(lái)時(shí)，我在吃飯。
【4】在過(guò)去，when從句動(dòng)作發(fā)生時(shí)，主句動(dòng)作已完成
解釋：表示在過(guò)去，當(dāng)從句包含的動(dòng)作發(fā)生時(shí)，主句的動(dòng)作在從句動(dòng)作發(fā)生之前已經(jīng)完成了。
句子結(jié)構(gòu)：when從句用過(guò)去式，主句用過(guò)去完成時(shí)。
例句：
When I got up,my mum had already (taken breakfast and) left.
當(dāng)我起床的時(shí)候，我媽媽已經(jīng)(吃了早飯)離開了。
The newsreel had almost finished when I went to the cinema.
我到電影院的時(shí)候新聞片幾乎要演完了。
I had only danced with Mary about three minutes when someone cut in.
我和瑪麗剛剛跳了大約三分鐘的舞，就有人來(lái)截舞。