昨天是我14岁的生日。我邀请了五个好朋友去肯德基吃晚餐，丁逸是其中之一。可是，让我吃惊的是，张方和丁逸一起来了，而我和张方的关系并不怎么样。我没有替张方买单，因为他是个不速之客，也并不受欢迎。后来我告诉了爷爷奶奶和爸爸妈妈这件事，爸爸妈妈认为我这样做是可以接受的，而爷爷奶奶对此不太高兴。爷爷奶奶觉得殷勤好客是中国人的传统美德。张方来参加我们的聚会，表明他愿意主动和我交朋友，我不应该拒绝。我自己认为我的做法是对的，因为是否付钱是一个原则问题。要是我替张方付了钱，别的同学未经邀请也来的话，我也要替他们付钱吗？

短文中所用到的词：
traditional virtue传统美德 hospitable好客的 an unexpected guest不速之客 on good terms with somebody与……关系好 practice做法 acceptable可以接受的 turn one's back on拒绝 a matter of principle原则问题

Yesterday is my 14th birthday. I invited 5 good friends to have dinner in KFC. Ding Yi is one of them. However, to my surprised, Zhang Fang came with Ding Yi. And, I am not in good terms with Zhang Fang. I did not pay for Zhang Fang, because he was an unexpected quest and unwelcome. And then, I told this to my parents and grand parents. My parents thoughts my behavior is acceptable. But, my grand parents were not happy about this. They thought hospitality is our traditional virtue in China. Zhang Fang joined our party showed that he would like to make friend with me, thus, I should not turn his back on. But, I thought my action is right because paying money is a matter of principle. If I paid for Zhang Fang, should I pay for other class mates without inviting?