VS
Farewell (=to fare you well)!(较正式, “再见”常含有“永别了或不容易再见面)
Goodbye!Thank you for your attention. (再见!谢谢诸位捧场。”这是演讲人结束演讲时的用语)
VS
Good luck to you! (祝你成功或顺利!是祝愿某人顺利完成某事或一路平安时的告别用语)
Good morning! (有时可以用作上午分别时的告别用语，这时两个词多重读)
VS
Good night! (晚安!一般是在晚上睡觉前分别时说的。如: Good night! Thanks again for coming. 晚安!再词谢谢光临。但美国人有时在下班时也互道一声“Good night.”表示今天不再见面了)
Bye-bye! (不太正式的告别用语。熟人之间常用)
VS
Bye-now! (重在强调时间的短暂)