A、By informing people that it’s an incurable disease. B、By providing effective medicine to stop its transmission. C、By disciplin

W: Our President, since leaving office five years ago, has spent a huge amount of time promoting AIDS awareness and prevention.
M: That is the thing I have been doing.
W: I know you just came back from Johannesburg, South Africa, part of your six-nation tour of Africa.
M: Right. You know, Africa has been more affected by AIDS than any other place in the world.
W: Why?
M: I think that’s partly because there were not systems in place both to prevent people from contracting it and spreading it.
W: How is your work getting on?
M: I think we are beginning to make some headway not only in Africa, but in other places where it’s a problem.
W: Can you name some?
M: It is spreading worldwide, growing even faster now in terms of the rate of increase in the former Soviet Union and the Caribbean, India, China.
W: I know your foundation is making a great deal of progress. Is it reasonable to expect that it can be brought under control?
M: Well, yes, but you have to take care of education and prevention and care and treatment at the same time, and the two things speed up each other.
W: How should we understand they speed up each other?
M: When you’ve got to treat people, you’ve got to overcome any kind of cultural dislike, talk about it and get young people to behave responsibly and you’ve got to do whatever you can to get as many people tested as quickly as possible but keep in mind that this is a disease that’s one hundred percent preventable.
19. What has the president been doing since leaving office?
20. Why has Africa been more affected by AIDS than any other place in the world?
21. How can a nation completely control AIDS?