把你的句子写出来,就可以解答了.快.例句：He came back late,by which time all the guests had alredy left.ok，应该是：He came back late, at about 9:00 pm ,by which time all the guests had alredy left.你的句子很可能漏了一个时间状语------ at about 9:00 pm 。
变成你要的结构就是：
He came back late, at about 9:00 pm ,by which time all the guests had alredy left
== By the time he came back quite late, at about9:00 pm all the guests had alredy left.
-------这大概就是你想表达的吧 ？请问By the time he came back late是一个什么类型的句子是时间状语从句部分+ 主句（all the - - - - ）.