28. Why are race walkers conditioned athletes?
A. They must run long distances.
B. They are qualified for the marathon.
C. They have to follow special rules.
D. They are good at swinging their legs.
【答案】C
答案解析：细节理解题。此题要求正确理解conditioned词义。Conditioned此处应理解为“有条件的；受条件制约的”。然后根据文中第二段第三句话“But the sport’s rules require that a race walker’s knees stay straight through most of the leg swing and one foot remain in contact (接触) with the ground at all times.”可知，这个条件就是竞走运动的特殊规则，即要求竞走运动员的膝盖要在几乎整个摆腿的过程中保持绷直，并且全程要有一只脚和地面保持接触。由此可知，答案选择C。
29. What advantage does race walking have over running?
A. It’s more popular at the Olympics.
B. It’s less challenging physically.
C. It’s more effective in body building.
D. It’s less likely to cause knee injuries.
【答案】D
答案解析：细节理解题。根据文章第四段（段落大意：竞走对身体的冲击力不像跑步那样多）和文章第五段第一句话“As a result, she says, some of the injuries associated with running, such as runner’s knee, are uncommon among race walkers.（句子大意：和跑步有关的一些损伤，比如跑步者的膝盖伤，在竞走运动员里是不常见的。）”可知，相对于跑步，竞走造成膝盖受伤的可能性要小，所以答案选择D。
