前句我认为可以互换
第二句中不可用by,因为by是介词,而 he came back是句子.by 不可以引导从句,要用的话应该这样：
She had lived in the house by the time he came back.这里 he came back是定语从句,修饰time.注意 主句这时一般用完成时
by与until ,before区别.
前句我认为可以互换
第二句中不可用by,因为by是介词,而 he came back是句子.by 不可以引导从句,要用的话应该这样：
She had lived in the house by the time he came back.这里 he came back是定语从句,修饰time.注意 主句这时一般用完成时