has been doing与had been doing,这两个时态分别代表怎样的概念,表示怎样的动作发生,用于何种情况,请大家分别具体解释一下它们所用的场合

has been doing与had been doing,这两个时态分别代表怎样的概念,表示怎样的动作发生,用于何种情况,请大家分别具体解释一下它们所用的场合
英语人气:194 ℃时间:2019-10-19 04:07:19
优质解答
has been doing表示动作到现在为止一直在做
I have been waiting for you for an hour.
had been doing表示动作到过去某一时刻为止一直在做
I had been waiting for you for an hour until you finally reached.
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