按要求对下列句子进行句型转换。

1. This is my sister. (变为复数句)
                                                                                                                           
2. He is twelve years old. (对划线部分提问)
                                                                                                                           
3. Danny can fly a kite. (改为一般疑问句)
                                                                                                                            
4. I have two chairs. (改为否定句)
                                                                                                                            
5. Li Ming and Jenny want to go shopping today. (对划线部分提问)
                                                                                                                            
6. It's 6:40 now. (对划线部分提问) 
                                                                                                                            
7. The book is under the desk. (对划线部分提问)
                                                                                                                            
8. May I take your picture? (作否定回答) 
                                                                                                                            
9. Walk quickly,please. (改为否定句)  
                                                                                                                             
10. Are you hungry? (作肯定回答)