(B)
A marathon is a running event (赛事) with a distance of 42.195 km. It takes people a lot of time and energy to finish (结束). Why do people run a marathon? Here are some posts.

() 5. What is marathon?
A. A running event.
B. A sports meet.
C. A swimming club.
D. A running club.
() 6. According to Lisa, running a marathon is a good way to .
A. exercise
B. meet new people
C. travel
D. climb mountains
() 7. Why do people like the Midnight Sun Marathon?
A. People love mountains in Norway.
B. People run at night with the sun still in the sky.
C. People in Norway are kind and polite.
D. Norway has snow-capped mountains.
() 8. According to Leo, running a marathon can .
A. let people play
B. be easy for old people
C. help feel something new
D. help old people keep fit
() 9. What is the main idea of the passage?
A. People run a marathon for different reasons.
B. People can run a marathon at any age.
C. There are different marathons around the world.
D. There are only two reasons why we run a marathon.

5. A 6. C 7. B 8. C 9. A

【分析】
这是一篇关于马拉松的英语阅读理解题，需结合原文内容逐一分析各题：
1. 第5题询问马拉松的定义，直接定位原文第一段第一句找对应信息；
2. 第6题询问Lisa的观点，定位Lisa的发言内容，提取她提到的跑马拉松的目的；
3. 第7题询问人们喜欢午夜太阳马拉松的原因，定位Lisa介绍该马拉松的相关语句；
4. 第8题询问Leo的观点，定位Leo的发言，提取他提到的跑马拉松的作用；
5. 第9题询问文章主旨，需总结两人发言的核心内容，确定整体主题。
【解析】
5. 根据原文第一段第一句“A marathon is a running event (赛事) with a distance of 42.195 km.”可知，马拉松是一项跑步赛事，对应选项A，故选A。
6. 根据Lisa的发言第一句“Some people run a marathon to travel.”可知，Lisa认为跑马拉松是旅行的好方式，对应选项C，故选C。
7. 根据Lisa介绍Midnight Sun Marathon的最后一句“People run at night with the sun still in the sky!”可知，这是人们喜欢该马拉松的原因，对应选项B，故选B。
8. 根据Leo的发言第一句“Some people enjoy something new by running a marathon.”可知，Leo认为跑马拉松能让人体验新事物，对应选项C，故选C。
9. 文章通过Lisa和Leo的发言，分别介绍了人们跑马拉松的不同原因（旅行、体验新事物等），主旨是人们跑马拉松有不同理由，对应选项A，故选A。
【答案】
5. A 6. C 7. B 8. C 9. A
【知识点】
英语阅读理解、细节理解题、主旨大意题
【点评】
本题考查学生对英语阅读理解文章的细节查找和主旨概括能力，题目以基础细节题为主，难度适中，需学生仔细阅读原文对应内容即可解答。
【难度系数】
0.6