1. It _____ going to rain soon.

2. I ____ having a picnic with my friend.

3. Sam ___ flying a kite in the park.

4. They ____ sing an English song.

5. ____ you cleaning your room?

【答案】is am is are Are

【解析】

Be 动词使用口诀：

I 用am ，you 用are，is 跟着he / she /it 。

至于复数（we /they / you）,全部都用一个are .