题干
By the time I got back to school, the bell had rung.直到我回到学校，铃已经响了。
____直到……时候
指从过去某一点到从句所示的时间为止的一段时间。如：
By the time we got to his house, he had finished supper.
在我们到达他就已经吃完了晚饭。
答案(点此获取答案解析）
by the time
