had been doing是什么时态怎么翻译

　　Until this summer, China had been doing that carefully.

　　截止今年夏天，中国一直在审慎地这么做。

　　I had been doing the work for two hours when the teacher came.

　　老师来时那件工作我已做了两小时了。&当时工作尚未完成，所以老师来了我还继续在做。

　　Everybody knew what he had been doing all those years.

　　大家都知道那些年他在做什么。

　　It was, after all, what we had been doing all along.

　　毕竟，我们一直在做这一行。

　　I had been doing what you're almost certainly doing now.

　　我做的.是你们肯定现在在做的。