读下列教材原句并感知黑体部分的共性。
1．It's not a real sport, is it?
2．That sounds interesting, doesn't it?
3．Hi! It's a beautiful day, isn't it?
4．By the way, our school soccer team won at last, didn't they?
5．The Sports Day is coming soon, isn't it?
我的发现：
附加疑问句由两部分组成，前一部分是一个(1)__陈述句__，后一部分是一个简短的(2)__问句__。前后两部分的人称和动词(3)__时态__要保持一致，并遵循“前肯定后否定，(4)__前否定后肯定__”的原则。
