A、19 years old. B、13 years old. C、15 years old. D、17 years old. A细节题。女士说Clement刚刚打破了男子400米的世界纪录，今年才19岁。因此，A是正确答案．

W: Do you like to run?
M: Yeah, when the police are chasing me.
W: Fast like Clement?
M: Who?
W: Kerron Clement. He just broke the world record in the 400 meters. Did you know that he’s only 19 years old? Did you see it on the news?
M: I heard a bit about it.
W: Okay. Well, let’s look at the rest. This Florida sophomore ran the 400 meters in 44.57 seconds at the NCAA Indoor Track and Field Championships. He broke the mark of 44.63seconds set by Michael Johnson in 1995.
M: Hey. I’m fast. I could beat him any day.
W: Yeah, only if there is a $20 bill blowing in the wind in front of you. Let’s go back to the story now. Clement is from Trinidad and Tobago and moved to the United States when he was 13. He was a highly desirable athlete at La Porte High School in Texas. Big sports schools like Louisiana State University, Texas and Tennessee were after him. He chose Florida and wasted no time in making his mark. He won the NCAA championship in the 400 meter hurdles and then won the world junior championship in the same event. At the junior championships, Clement competed for the United States after earning his U.S. citizenship last summer. He probably could have gone to the Olympics for Trinidad and Tobago last year. but preferred to become an American. Why do you think he wanted to become an American?
M: Probably America is his new home and it has better living conditions than back home.
W: Yeah. something like that. He said he loves competition and he wants to train with the best in the world, the Americans.
Questions:
19. Why does the woman say "Yeah, only if there is a $ 20 bill blowing in the wind in front of you"?
20. What does the woman mean by "Yeah, something like that"?
21. How old was Clement when he broke the record of 400 meters?