按照要求进行句型转换。

1. She is doing her homework. (改为否定句)

    She __________ __________ her homework.

2. They are looking at the blackboard. (改为一般疑问句)

    __________ __________ __________ at the blackboard?

3. Tom is playing basketball. (对画线部分提问)

    What __________ __________ __________?

颗粒剂分为可溶性颗粒剂和泡腾颗粒剂两种。