by the time
1
到...时候, 当...时
used to indicate a point in time before which an action or event has occurred or will occur
- By the time she finishes her degree, she will have learned a lot.
到她完成学位的时候，她会学到很多东西。
- By the time they reached the theater, the movie had already started.
等到他们到达剧院时，电影已经开始了。
- By the time the concert ends, it will be midnight.
到音乐会结束时，将会是午夜。
- He hopes to have traveled to at least 20 countries by the time he turns 30.
他希望到30岁时至少去过20个国家。