哪部分提问?
否定句 The girl isn't playing the piano at the party.
一般疑问句 Is the girl playing the piano at the party?没写。。army day is on august 1st（on august 1st）提问What is the girl doing at the party?She is playing the piano at the party.When is the army day?army day is on august 1st（on august 1st）提问这道题就是When is the army day?