I am doing my homework now.
我现在正在做功课
I was doing my homework this time yesterday.
昨天的这个时候我正在做功课
I have finished my homework.
我已经做完作业了
I have being finished my homework.
我一直都在做功课,还要继续做下去
I had read the book by last month.
上个月我就读完了那本书
I had being read the book for the whole June.
整个六月我一直都在看那本书,还要继续看下去
肯定对哦