将下列句子改成否定句和一般疑问句并作肯定和否定回答。
1、At the moment, Tom is playing the piano.
2、Listen, they are speaking French.
3、 Liu Ming is skating in the sports hall now.
4、Su Yang is catching insects.
5、I am doing my homework now.
6、 They are walking to the park.
7、 The little boys are learning to ski.
