Read the following paragraph and underline the topic sentences.
Claudia is destined to be an excellent long distance runner. First, there are her physical attributes. She is long-legged and has a tremendous stride. She also has great natural endurance and an at-rest heart rate of sixty beats per minute. Next comes her mental toughness. She is a tremendous competitor who will extend herself to exhaustion to win a race. She has the strength to block out pain and concentrate on her race during those last few hundred yards where most runners tend to wilt.Finally, Claudia surpasses most athletes in dedication. She runs five to ten miles a day in morning and evening sessions at least five days a week. She maintains this schedule ten months out of the year, and while most high school athletes sit out the summer , Claudia trains and competes in AAU competit1on. If she can maintain this dedication for another two years, she has an outside chance of being invited to the Olympic trials.
【正确答案】：Claudia is destined to be an excellent long distance runner.
【题目解析】：p158
