Sentences structure:
Questions using this structure is for people to give positive or negative choices. it means : are/do… or not?
Subject+有没有+object？
eg. 你有没有吃饭？/Have you eaten or not?
positive answer: 我吃了。
negative answer: 还没有/not yet. （=我还没有吃。/I haven’t.）
Subject+是不是+object？
Subject+(Time)+忙不忙？
eg. 你今天忙不忙？/ Are you busy or not today?
positive answer: 我很忙。
negative answer: 我不忙。
Subject+胖不胖？
Subject+漂亮不漂亮？