We say goodbye before going to Vietnam. ☊ 
Chúng tôi nói tạm biệt trước khi đi Việt Nam. ☊ Conjunctions like: Tạm biệt. → →
Tschüss. ☊ Tạm biệt. ☊ (Lektion 1, Nr. 9) Vielen Dank und auf Wiederhören. ☊ Cám ơn và chào tạm biệt. ☊ (Lektion 69, Nr. 994) Auf Wiederhören. ☊ Tạm biệt. ☊ (Lektion 85, Nr. 1234) We waved them goodbye. ☊ goodbye ☊
She hurried away without saying goodbye. ☊ hurry ☊
She was upset that he had left without saying goodbye. ☊ upset ☊
wave sb sth: My mother was crying as I waved her goodbye. ☊ wave ☊
wave sth to sb: My mother was crying as I waved goodbye to her. ☊ wave ☊
without doing sth: He left without saying goodbye. ☊ without ☊