by the time引导的时间状语从句和when引导的时间状语从句有区别吗eg.:By the time I got outside the bus had already left.When she got to school,she realized she had realized she had left her backpack at home.
问题描述：
by the time引导的时间状语从句和when引导的时间状语从句有区别吗
eg.:By the time I got outside the bus had already left.
When she got to school,she realized she had realized she had left her backpack at home.
答
我举个例子
When the teacher came in ,I was reading.
I had just fallen asleeep when the telephone rang.
I was just about to go out when he came in