.All the people sing a song together at his birthday party.
改为一般疑问句：Do.All the people sing a song together at his birthday party.?
改为过去时：.All the people sang a song together at his birthday party.
用What提问 ：What do.all the people do together at his birthday party.? what对事情提问
用When提问：When.do all the people sing a song together ? when对时间提问