,____I was going out ,it began to rain.A.when B.while C.as 为什么不能用when?

,____I was going out ,it began to rain.A.when B.while The key is C.as . 我刚要出去，天就下雨了。--------------------------------------------as-- 指一个动作紧接着一个动作发生，从句通常用进行时。 (不能用when , 因为when 指两个动作同时发生,而不是一前一后。)● I saw Mary as she was getting on the bus. 玛丽刚要上车，我就看到她。● As he was eating his breakfast, he heard someone knock at the door. 他正在吃早饭的时候听见有人敲门。● Someone patted me on the shoulder as I was standing before the shop window.

,老师，我发现：when好象不是＂同时发生＂．例如：When I opened the window,I saw him come up.opened the window一定是先发生的，然后才能saw him come up．while和as好象都是真正意义上的＂同时发生＂．

,按老师请面讲的when的用法，这道题用when好象也不错．when I was going out ,it began to rain.表示＂不满＂．译作：＂我刚要出去，真烦人，天就下雨了＂．

表示＂不满＂．译作：＂我刚要出去，真烦人，天就下雨了＂．你说的一点也不错，用不同的连词有不同的语感，问题是你们老师会算你对吗！？ 孙老师

老师，我对when while as的区别是这样理解的：首先应该知道：when 点／线while 线as　点／线然后判断步骤：第一步，判断从句是＂点＂，还是＂线＂．第二步，根据各自的用法对号入座．如果从句是＂点＂，就想when 和 as，有两种情况必须用when:１．突然２．不满有一种情况必须用when：１．一边．．．一边，随着其他情况两者可换用．如果从句是＂点＂，就想when和while 和 as，有两种情况必须用when:１．突然２．不满有一种情况必须用while：１．对比有一种情况必须用when：１．一边．．．一边，随着其他情况三者可换用．老师，这样理解行不行啊？

上面有几个字打错了，正确的如下：老师，我对when while as的区别是这样理解的：首先应该知道：when 点／线while 线as　点／线然后判断步骤：第一步，判断从句是＂点＂，还是＂线＂．第二步，根据各自的用法对号入座．如果从句是＂点＂，就想when 和 as，有两种情况必须用when:１．突然２．不满有一种情况必须用as：１．一边．．．一边，随着其他情况两者可换用．如果从句是＂点＂，就想when和while 和 as，有两种情况必须用when:１．突然２．不满有一种情况必须用while：１．对比有一种情况必须用as：１．一边．．．一边，随着其他情况三者可换用．老师，这样理解行不行啊？

上面有几个字又打错了，正确的如下：老师，我对when while as的区别是这样理解的：首先应该知道：when 点／线while 线as　点／线然后判断步骤：第一步，判断从句是＂点＂，还是＂线＂．第二步，根据各自的用法对号入座．如果从句是＂点＂，就想when 和 as，有两种情况必须用when:１．突然２．不满有一种情况必须用as：１．一边．．．一边，随着其他情况两者可换用．如果从句是＂线＂，就想when和while 和 as，有两种情况必须用when:１．突然２．不满有一种情况必须用while：１．对比有一种情况必须用as：１．一边．．．一边，随着其他情况三者可换用．老师，这样理解行不行啊？

老师，前两个都有错别字，看第三个．谢谢老师！

老师，这样理解行不行啊？

, we saw him twice. 我们在美国期间，见过他两次。● While we were talking, he came in. 我们正说着话，他来了。while--2.表示主句与从句对立, 意思是这边在干某种重要的事，而另一边在享受等。● We are cleaning the classroom while they are playing football. 我们这儿在打扫教室而他们在踢足球。● The soldier faces the powder while the beauty powders the face. 前方吃紧，后方紧吃。（战士面对炸药，美人在往脸上擦粉。）as--1.一边...一边，随着● She was doing her homework as she was listening to the music.● As she grew older, she became more beautiful.as--2. 指一个动作紧接着一个动作发生，从句通常用进行时。 ● As I was going out, it began to rain. 我刚要出去，天就下雨了。● I saw Mary as she was getting on the bus. 玛丽刚要上车，我就看到她。● As he was eating his breakfast, he heard someone knock at the door. 他正在吃早饭的时候听见有人敲门。●Someone patted me on the shoulder as I was standing before the shop window.