[高考必背英语句型]when引导的从句

    　句型15

　　when引导的从句

　　when除了用来引导主语从句、宾语从句、时间状语从句、表语从句和定语从句，还有一种用法值得关注，那就是when引导并列分句，意思是“这时突然;就在那时”，强调另一个动作的突然发生。常用于以下句型中：(1)、主语+ be doing… when…意思是“正在做某事这时……”;(2)、主语 + be about todo…when…;(3)、主语+be on the point of (doing)…when…意思是“正要去做某事这时……”

　　[例句]

　　One day Chuck was on a flight across the Pacific Ocean whensuddenly his plane crashed. 有一天，Chuck正在太平洋上飞行，这时他的飞机突然爆炸了。

　　I don’t know when he will arrive. 我不晓得他什么时候到达。

　　I thought of the happy days when I was in Beijing.我想起了在北京时的那段快乐日子。

　　I believe the time will soon come when there will be noweapons in the world. 我相信世界上没有武器的日子不久就会到来。

　　I was walking along the river when I heard a drowning boy cryfor help. 我正在河边行走，这时我突然听到一个落水男孩求救。

　　I was about to leave when it began to rain. 我刚要离开，这时下雨了。

　　I had just finished my exam paper when the bell rang,announcing the class was over. 我刚做完作业，下课铃响了。

　　I thought of the happy days when I was in France.我想到了在法国时那段快乐日子。

　　I believe the time will soon come when there will be noweapons in the world. 我相信世界上没有武器的日子不久就会来临。

　　[比较]

　　I was walking along the street when I caught sight of atailor’s shop. 我正在街上走，这时我看见一家裁缝店。

　　I was walking along the streets. Just at the moment I caughtsight of a tailor’s shop. 我在街上走。就在那时我看见一家裁缝店。