had been doing 和 had done的区别

had done 是过去完成时,指发生在早于过去某个时间的行为,该行为到那个时间业已结束。had been doing  是过去完成进行时,同样指发生在早于过去某个时间的行为,但这个行为到那个过去时间还在进行。例如：By He had done the work by ten o'clock this morning。到今天上午十点钟,他已完成了这项工作。He had been doing the work by ten o'clock this morning。  到今天上午十点钟,他还在干着了这项工作。He could remember a time when he had worked like that himself。他还能记得自己一度工作起来的那个样子He could remember a time when he had been working like that himself。他还能记得自己当时一直在工作的那个样子。