参考答案：C

解析：[听力原文]19-22M: Is that a map Are you going sailing or something W: I wish. It’s a hurricane-tracking chart. It’s a map of tropical ocean areas southeast of us. It follows the development of tropical storms, even hurricanes. They develop in the Caribbean and move around the Atlantic and here on the Florida coast. We got hit a lot by those winds or rain in July or August.M: Do you think that the tropical storm is on the way W: Too early to tell, but we need to be prepared. The radio mentioned possible evacuation routes.M: Really It’s that serious W: You’d better believe it. Late summer is hurricane season. The television updates locations and speeds every hour.M: What did they say is out there now W: A couple of tropical depressions, two storms and two hurricanes.M: what’s the difference W: Wind velocity. A depression is the least serious actually, and a hurricane is the most serious.M: How serious are the winds in hurricanes W: They have sustained winds of 74 mph and up.M: What are the names on the map W: David, Arlene, Francisco, and Gina. You know weather forecasters give the hurricanes the names of people to make storms easy to identify.M: I wonder what the status of the storm is now.W: You can. turn on the television; it has the best coverage. There is an update coming up in five minutes.19. what is the conversation mainly about 主旨题。由对话中的a hurricane-tracking chart及here on the Florida coast可知，对话是针对可能影响佛罗里达的大气情况展开的，所以C正确。