WHEN和WHILE引导的让步状语从句有何不同?（WHILE是作"尽管"讲时）

让步状语从句:连接让步状语从句的连接词有：although,though,even if,even though,however,whatever,whenever,whoever,whichever.1：when和while引导的时间状语从句与这一时态连用.所以区别when和while的用法成了这一单元的难点.（一）、when,while都有“当……时候”的意思.when既可表示某一点时间,也可以表示某一段时间 .在when引导的时间状语从句中,其谓语动词可以是延续性的,也可以是非延续性的,可与主句中的谓语动词同时发生,也可在其后发生.例如：1、I was just reading a book when she came into my room.她走进我房间时,我正在看书.2、Were you writing when the teacher came in?老师进来的时候,你在写信吗?3、When he was a child he was always trying out new ideas.他小时候就常常试验一些新的设想.（二）、while只能表示某一段时间,不能表示某一点时间.在while引导的时间状语从句中,其谓语动词只能是延续性的,而且也只能与主句中的谓语动词同时发生或存在.例如：1、While Jim was mending his bike,Lin Tao came to see him.正当吉姆修自行车时,林涛来看他.2、You can’t do your homework while you’re watching TV.你不能一边看电视一边做家庭作业.（三）、另外,when和while的区别还在于：while引导的时间状语从句多用进行时态,而when引导的时间状语从句多用一般时态.例如：1、While they were talking ,the bell rang.正在他们谈话的时候,上课铃响了.2、I was doing my homework when my mother came back home yesterday evening.昨天晚上妈妈回家的时候,我正在做家庭作 １ Although (though) I gave him some advice,he didn’t take them.２ John continued to work hard even if (even though) he felt sick.３ Whatever you do,I will support you.==No matter what you do,I will support you.４ Whoever you may be,I will not let you in.===No matter who you may be,I will not let you in.５ However difficult it may be,we will overcome it.=== No matter how difficult it may be,we will overcome it.注意：一般情况下,although等于though,even if等于even though,however等于no matter how,wh-ever等于 no matter wh-．