这是过去完成进行时 下面的是在百度中找的，你可以看一下。。希望会有用咯。。。结构主语 +had+been +v.ing （因为是过去时had无人称变化）编辑本段比较过去完成进行时与过去完成时的用法很相近，它通常表示某个过去正在进行的动作或状态，持续到过去某个时刻，还未完成，一直持续到之后的当前才结束He had been waiting for two weeks． He was still waiting．（有一个表示一段时间的状语）Up to that time he had been translating those books．（He was still translating at “that time”．）He had been writing the letter till two o'clock．He was now thirty years old．He had been gambling since he was ten．（He was still gambling at thirty．）He had been standing there in the sun．（没有时间状语）He had been thinking about his marriage．不过这种时态并不一定表示这个过去动作将持续下去：He came back at seven．He had been waiting for her two hours．（At seven he did not wait any more．）He stopped swimming．He had been swimming for the last three hours．编辑本段特别含义1）尚未完成：He had been writing the novel．（He had not finished it yet．）2）企图：He had been studying the meaning of this proverb．（He was trying to study it．）3）未得结果：We had been studying what our enemy had said．（But we were not able to understand it．）4）最近情况：He had been quarrelling with his wife．（lately）5）反复动作：He had been asking me the same question．（Many times）6）情绪：What had he been doing？（不耐烦）编辑本段特点这种时态很少用在否定句中，而多以过去完成时代替：He had not practised English for many years．（普通说法）He had not been practising English for many years．（少见）这种时态还可用在said，supposed等引起的间接引语中，代替现在完成进行时：He said，“I have been speaking to John．”= He said that he had been speaking to John．He thought，“She was watching me when I passed．”= He thought that she had been watching him when he had passed．
比如：I have been working here for 3 years. 我已经再这工作3年了。 “已经”，所以用"现在完成时"的结构"have done" (就是句子里的have been) 从句子可以推测出，我现在还继续“正在”这里工作，所以用现在进行时的结构"be doing"（就是句子里的been doing） 二者结合就是have been doing