we are classmate,we are friendsclassmate为什么不用复数 friends为什么要用复数需要专业一点的回答

Are we classmate?yes,we are(修改病句) we are classmate,we are friendsclassmate为什么不用复数 friends为什么要用复数需要专业一点的回答 We have a new classmate.对a new classmate提问 we have a new classmate(改疑问句) we are we are we are we are we are we are we are we.are we are we are We are we are WE ARE are we