by the time 的用法 请指教 能切中要害那么在请问大侠们,by the time our teacher came in ,we had started speaking English.这句话对吗

表示在某个时间之前

表示到这时已经
用于过去,就是过去完成时
By the time I was 8, she Had already been famous
用于将来,就是将来完成时 By the time this is finished,
we will have been all tired

到那个时候止(不过具体的是到什么时候要根据句子的意思而定).
by the time 不仅仅是过去完成时的标志,确切地讲,应该是完成时的标志,因为它可以表示成过去完成时,现在完成时,还可以表示将来完成时的标志.这就要看具体的句子所表达的意思了.

"顺便问一下",前文已经有话,说完后用它再问一些或转折

by the time 有两个意思:
一:by the time可以翻译为:这时候,在此时.相当于at the/that time.
By the time he had lost contact with the Party.
这时他已和党失去联系.
By the time we had settled in the third bus.
这时我们已在第3辆大汽车里坐好.
二:by the time,意为:在.之前已经.
by the time our teacher came in ,we had started speaking English.
在老师进来前,我们都已经开始讲英语了.
你这句话的结构是对的.只是翻译过来感觉有点不是很顺口.
by the time when got to the bus station,the bus had left.
在我们到达车站时,汽车早就开走了.
by+时间名词.意为：“到…时（已发生某事）,此时谓语多用完成时；最晚、不迟于…,在…之前”.如：by now/then/this time/next Friday/the end of/three o`clock等.
By the end of last year,another new gymnasium had been completed.(2003上海·春）到去年年底,又有一座新体育馆峻工了.