现在进行时态的肯定式、否定式、疑问式及简略回答。

1)肯定式：be+v-ing

She is singing in the next room.

2)否定式：be+not+v-ing

The students aren’t cleaning the room.

3)一般问句：be动词提前。

肯定答语Yes，主语+be。

否定答语No，主语+be not。

Are you playing the computer game? Yes, I am. /No, I am not.

4)特殊问句：对谓语动词进行提问的：What+be +主语+doing+其他?

What is the old man doing under the tree?

对其他成份进行提问的，疑问词+一般疑问句?

Where is the boy swimming?