句型转换（每空一词）。    

1. We are going hiking this Sunday. (对画线部分提问)   

                   are you               this Sunday?    

2. I often take walks after supper. (改为同义句)

    I often                                          walk after supper. 

3. The weather in Nanjing is very hot. (对画线部分提问)   

                                 the weather like in Nanjing?    

4. They are going to the Great Wall. (对画线部分提问)   

                  are they              ?    

5. They walked two hours in the field. (对画线部分提问)   

                              did they walk in the field?

GFM中G、F、M各代表什么意思？