19. It's time for class. 上课时间到了。　

18. Sit down, please. 请坐。　

17. Come in, please. 请进。　

16. May I come in? 我能进来吗？　

15. I have to go now. 我必须走了。　

14. See you later. 待会儿见。　

13. See you tomorrow. 明天见。　

12. Good-bye, Mike. 再见，迈克。　

11. Good night, Jane. 晚安，简。　

10. She is very well, thank you. 她很好，谢谢。