A、Which country should be allowed to have nuclear weapons. B、The time for their next coffee appointment. C、Whether it is meaning

M: Are you going to the demonstration to help stop the spread of nuclear weapons tomorrow, Cleo?
W: No, Simon. I hate demonstrations. I have heard the police will be standing by with tear gas.
M: Yes, but North Korea boasts it has nuclear arms.
W: One hundred ninety countries have signed the Nuclear Non-Proliferation Treaty but the issues are just too complex. There are two sides to every story. I don’t understand it and I have no intention of going to a demonstration. Demonstrations don’t seem to accomplish anything anyway.
M: Several demonstrations have changed politician’s minds throughout history. As a responsible citizen I think it is important to stand up for what you believe in.
W: Leave it to someone else. As I said, if you listen to both sides of a story, both sides have some good points. Why should I demonstrate and risk getting hurt for something that I am not even sure is right?
M: You are not likely to get hurt. This will be a peaceful demonstratioa I have spoken to the organizer for the university group. He insists that this will be peaceful. He advocates if you want world peace, peace begins at home—and that means right here in this city.
W: You go if you want Simon, but I plan to study for my physics exam.
M: It would only take two hours of your day. The bus leaves the campus at 11:30 and leaves downtown to return to campus at 12:45. You could eat your lunch on the bus.
W: I am not going, Simon. Why don’t you ask the students in your political science class this afternoon if they want to go?
M: They are all going.
W: Okay, Simon. I need to meet my sister for coffee now.
M: Bye then. See you in physics class tomorrow.
19. What do the two speakers mainly disagree upon?
20. How does the woman react to the man’s persuasion?
21. What is the man’s purpose in talking with the woman?