He may be studding in his study.

他可能正在书房里学习。

I like studding English very much.

我非常喜欢学习英语。

I'm studding English.

我在学英语。

I hear that you are studding Roman history.

听说你最近在研究罗马历史。

But in our country. It only stay at studding and pursuing stage.

而在我国，还仅处于研究和推行阶段。