I bumped into Andy last night. 我昨晚偶然碰见安迪.
What a nice surprise 多么叫人惊喜的意外! What a coincidence! 真巧! 我们在这儿碰上了!
What an unexpected pleasure! 多么愉快的意外. A:Fancy meeting you here! 没想到会在这儿碰到你.
B:What a small world 人生何处不相逢. Nice talking to you. 跟你聊得很愉快.
