while前后都用过去式对不对 I played computer games while he read the books.这句对吗,为什么?怎么理

while前后都用过去式对不对 I played computer games while he read the books.这句对吗,为什么?怎么理 “催化剂在化学反应前后质量和性质都不变”对不对 I _____there for two days.为什么可以填stayed?不应该是现完么?那用一般过去式对不对内？ 关于while的一些问题while 1.主句和从句都用过去进行式2.主句用过去进行式`从句用过去式`问下这两种有什么区别? COULD YOU PLEASE TAKE GOOD CARE OF IT WHILE I'M AWAY?为什么CAN要用过去式 状语从句I saw a UFO while i was walking down the street yesterday.这里主句是过去式,那从句怎么用was walking 不是说主句是一般过去式,从句是过去式的某个形态 Time elapsed while I slept 这句话中为什么我觉得语法不对老师说 while前后必须+ing , 为什么这句话没有句中while可以用when替换么 When和While的用法和区别还有While是不是前后都是过去进行时,而When前面是过去进行时后面是过去式? while一定要用过去进行时吗while后可以接延续性动词的过去式吗?比如While i raed book,he watch tv.还是只能用过去进行时?具体! He met many problems__he was going over his lessons 为何用while while不是前后都要进行时么 while表示对比我印象中好像while表对比的时候前后句都要是延续性的动词? while用于进行时态的问题1.while i was running along,a dog ran across the road.2.last night my father was reading while my mother was sewing.while前后的时态怎么 确定.第一句只有while 后面的从句才用的进行式,主句则用 when和while的时间状语从句中前后时态都有什么, 关于when和while前后时态的题..when和while的前后事态怎么用总是分不清楚 .以下是几道题..最好做完说说为什么用这个时态...比较笨 1 She (see)the police car while she (drive)to work2 I (make) the dinner when the ___ you become more experienced,you'll be more confident.为什么as对?as不是前后没有时间间隔的吗?还有,when、while对不对? They were singing while we were dancing.和He came while I was having shower.这两个句子都是时间状语从句.为什么第一个的主句用过去进行时第二个则用一般过去式. I helped him clean the room为什么clean 是原形；那My teacher asked me (clean)the office,clean加ed吗什么情况前后都变,为什么有时后面的一个词就不变过去式 while((i