给下列问句选择正确答语，将序号填在题前括号里。
1. What is Mike doing? [ ]
A. I'm doing my homework.
B. He is doing his homework.
2. What time do you go home?[ ]
A. It's 11:30.
B. At 11:30.
3. Do you want to go to the Children's Center?[ ]
A. Sure.
B. Yes, you do.
4. What is your grandma doing?[ ]
A. He is cooking lunch.
B. She is cooking breakfast.
