A friend invites you to dinner. What's the classic answer?

Are you trying to express? Still not going? If you want to express that you don't want to go, just send it: No! Experience it for yourself, it is more meaningful than any classic text, and the vernacular contains much more content than the spoken text! If you want to express it, send it: no! Then show up at the hotel 5- 10 minutes later at the scheduled time, bring a meaningful gift, or simply bring a bottle of Erguotou, and tell more in silence than they tell in voice! Good luck!