按要求改写句子。
（1）The children are playing football.(用what就划线部分提问）
                                               
（2）Many people like the spring. （改为否定句）
                                                  
（3）Did you buy presents on your holiday ?(否定回答）
                                                  
（4）I  am going to Shanghai at 3 o'clock.（用when 就划线部分提问)
                                                  
（5）I  went to school on foot (改为一般疑问句）