英语中说再见的常用说法是"Goodbye"，它来源于英语中的"God be with you"，意思是上帝与你同在。
其他常用的说再见的说法还有：
Farewell，意思是再见，告别。
See you later，意思是再见，待会儿见。
Take care，意思是保重，照顾自己。
例句：
Goodbye, teacher. Have a nice day. (再见，老师，祝你今天愉快)
Farewell, it was nice knowing you. (再见，很高兴认识你)
See you later, teacher. (老师，待会儿见)
Take care, teacher. (老师，保重)