by the time 是過去完成時和將來完成時的標誌詞。例如：*By the time the tests took place, the athletes had had a full 17 hours notice. (到檢測開始時，離運動員得到通知已經整整17個小時了)*By the time he will have arrived at my hotel. (到時他可能已經到達我住的賓館了)如果是系動詞 be，應該用過去時或將來時，例如：*By the time he died, he was amillionaire. (到他去世的時候，他已經是一位百萬富翁了)*By the time we get back from dinner, will be already in bed. 到我們吃完飯回來時，她可能已經睡下了。

by the time有一種用法，表示“到。。。為止”，一般和完成時連用。 如I had finished my homework by the time my mother came back. 當我母親回來的時候我已經完成了我的家庭作業。 當表示“。。。的時候”可以和when 互換。 如I will leave by the time you arrive.等你到了我就走，可以用when代替。