状语从句before比如：类似：it was a long time before we met again和完成时的：it is a long time since my brother joined the army这种类型的要怎么区分?

状语从句before比如：类似：it was a long time before we met again和完成时的：it is a long time since my brother joined the army这种类型的要怎么区分? Work on it had begun before my sister left.是时间状语从句吗? 英语时间状语从句1,“走之前把门关上”是不是应该时间状语用when引导,为什么不用before,若用before怎么翻译.2,The fire went on for quite some time _________ it was brought under control.为什么填before而不能填w before可以引导时间状语从句吗 before引导的状语从句例子 以before或after引导的状语从句有问!进入帮手例：It will be four days before they come back哪句系主句?哪名是从句? He wants【 to finish it】宾语【 before his mother finishes it 】时间状语从句做时间状语 我的分析对吗 it will not be long berfore we knowthe result before在这领导的是时间状语从句吗 让步状语从句表示什么意思从本身句义理解,比如 “从句对主句结果无影响”（类似这种的）帮助下 Firemen had been fighting the forest fire before they could get it under control.这里的before是什么意思?在---之前?它引导的是不是状语从句? 如何判断状语从句和强调句.比如it is……when/where it is……that bring your unbrella in case it rains 这句话中用的是in case+状语从句类似这种句式主句和从句各用什么时态啊 请问,状语从句中before的用法有哪些 怎样判断状语从句中引导词做什么句子成份啊 比如 you can throw it whatever you want 怎么看出,状语从句是修饰主句的动词或副词或形容词?如这个句子,是个状语从句It will not be long before we meet again ,我就不知道他修饰的是什么 from where it begins是名词从句还是状语从句? it引导时间状语从句与it引导主语从句有什么区别比如It was October 1st,1949 when the People's Republic of China was founded.此句为什么是it引导的时间状语从句而不是it做形式主语引导主语从句,when在从句中 状语从句和定语从句有什么区别?比如地点状语从句和先行词是地点的定语从句?