Question

wheniknewtherewasgoing为啥用when

Answer 1

英语中，连词when表示"当……时候"，引导的时间状语从句表示与主句动作同时或不同时，从句动词用延续或非延续性都可以。如：I'll telephone you when I get there tomorrow.明天我到那里的时候就给你打电话。但是在高一新教材Unit 15 "The necklace"中，就出现了when用作并列连词，表示"就在这时"(=and this time/just at that time)的用法。如：Tom was sitting near the fire when he heard a knock at the door.汤姆正坐在火炉边，这时他听到一阵敲门声。I was just going to speak when the doorbell rang.我正准备讲话，这时门铃响了。当并列连词when用于"就在这时，正在这时"的用法时，它所引导的并列句表示动作发生后，另一个并列句所表示的动作之后，一般不可以用其他词代替，常用于以下结构：1.was/were doing +when意思为"就在这时，正在这时"。如：I was walking in the street when someone called me from behind.我正在街上走，就在这时有人从后面叫我。They were discussing the problem when the teacher came in.他们正在讨论问题，就在这时老师进来了。2.was/were about to do...when意思为"正要/正准备做某事，就在这时……"。如：She was about to go out when an unexpected visitor came.她正准备出去，这时来了一位不速之客。We were about to set out when it began to rain.我们正要动身，就在这时开始下雨了
3.be+表示状态的介词短语+when意思为"正在做某事，就在这时……"。如：They were at work in the office thatafternoon when a big fire broke out.那天下午他们正在办公室工作，就在这时一场大火发生了。We were on duty in the classroom when a boy rushed in.我们正在教室里值日，就在这时一名男孩冲了进来。Li Ping was on his way home when two boys stopped him.李平正往家走，突然两个男孩拦住了他。
注意：在上述三种用法的结构中，when引导的句子不能放在句首。