我做某事英文

I'm starting doing sth. 或 I’m going to do sth.有时也可以有这个意思,这个在表示你开始做事情前可以用,比如 I'm going to read a book,意思是我打算看书了或我正要开始看书呢 总体而言,两个表达方式差别不大,可以看个人喜好使用.

i mainly did something..

I mainly do sth

be up to sth

I am doing sth。。。。eg:I am watching TV.我正在看电视。

sb. be in the middle of doing sth.