将下列句子改为否定句和一般疑问句并作肯定和否定回答。 1、Liu Tao is going to USA next month. 2、I will try my best to win the match. 3、There will be a singing contest tomorrow afternoon. 4、My father is going to buy a bike. 5、They are going to do some shopping tomorrow morning. 6、We will meet at six tomorrow evening. 7、I'll join them. 8、It is going to snow. 9、We are going to have a birthday party for Lily. 10、I will help you with your Maths. 11、My friends are going to see me this evening.