2.时间状语：Now,at this time,days,etc. look. listen

3.基本结构：主语+be +doing +其它

4.否定形式：主语+be +not +doing+其它

5.一般疑问句：把be动词放于句首。

6.例句：How are you feeling today?你今天感觉如何? He is doing well in his lessons.在课上他表现得很好。