1 there is a newpaper on the desk
q：is there a newpaper on the desk?
q：what is on the desk?
回答：there isn't a newpaper on the desk.
2 he is going to come now
q：is he going to come now?
q：when is going to come?
回答：he isn't going to come now
3 they like ice cream
q：do they like ice cream?
q：what do they like?
回答：they don't like ice cream.
4 he cleaned his shoes.
q：did he clean his shoes?
q：when did he clean his shoes?
回答：he didn't clean his shoes.