按要求改写句子。
1. This is my ruler. （改写为一般疑问句并作出肯定的回答）
                                                                                                       
                               
2. Her dresser is near her bed.(变为否定句)
                                                                                                            
3. My keys are on the sofa. (对画线部分提问)
                                                                                                             
4. He is my good friend. (改为复数句)