过去进行时中“when和while讲解与练习

过去进行时中“when和while讲解与练习 过去进行时表示过去某一时刻或者某段时间正在进行或发生的动作，常和表过去的时间状语连用，如： 1. I was doing my homework at this time yesterday. 　 昨天的这个时候我正在做作业。 2. They were waiting for you yesterday. 　 他们昨天一直在等你。 3. He was cooking in the kitchen at 12 o'clock yesterday. 　 昨天12点，他正在厨房烧饭。 过去进行时的构成： 肯定形式：主语+was/were+ V-ing 否定形式：主语+was not (wasn't)/were not (weren't)+V-ing 疑问形式：Was/Were+主语+V-ing。 基本用法： 1. 过去进行时表示过去某一段时间或某一时刻正在进行的动作。常与之连用的时间状语有，at that time/moment, (at) this time yesterday (last night/Sunday/week…), at+点钟+yesterday (last night / Sunday…)，when sb. did sth.等时间状语从句，如： 　　1）What were you doing at 7p.m. yesterday? 　　　昨天晚上七点你在干什么？ 　　2）I first met Mary three years ago. She was working at a radio shop at the time. 　　　我第一次遇到玛丽是在三年前，当时她在一家无线电商店工作。 　　3）I was cooking when she knocked at the door. 　　　她敲门时我正在做饭。 2.when后通常用表示暂短性动词，while后通常用表示持续性动词，而while所引导的状语从句中，谓语动词常用进行时态，如：When the car exploded I was walking past it. = While I was walking past the car it exploded. 3.when用作并列连词时，主句常用进行时态，从句则用一般过去时，表示主句动作发生的过程