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。