People are busy working every day, so they do not have enough time to do exercise. As a result(结果), many people become too fat. To keep our bodies healthy, we have to do exercise every day.
There are many kinds of exercise. Bending(弯腰) and stretching(伸展) help us move easily. Before we play ball games or swim, it is better for us to do bending and stretching first. This kind of exercise is sometimes called "warm-up exercise". Running is also good exercise. If we cannot run fast, we can jog. Jogging means running slowly. Before we run or jog, we must do warm-up exercises. And we should not run or jog in busy streets. The air there is often dirty. Some people like weight lifting(举重) because it can make their bodies strong. We also need to do some warm-up exercises before weight lifting.
()50. makes many people too fat.
A. Eating or drinking every day
B. Having no time to do exercise
C. Doing more exercise
D. Reading at home
()51. Before we , we must do warm-up exercises.
A. run
B. jog
C. work
D. both A and B
()52. is called "warm-up exercise".
A. Playing ball games
B. Swimming
C. Bending and stretching
D. Weight lifting
()53. Why do people like weight lifting?
A. Because it can make them work well.
B. Because it can make them thin.
C. Because it can make their bodies strong.
D. Because they don't like other exercise.

50.B 解析:细节理解题。根据“People are busy working every day, so they do not have enough time to do exer- cise. As a result(结果), many people become too fat.”可知,人们每天忙于工作,以至于没时间锻炼。因此很多人会变胖。故选 B。
51.D 解析:细节理解题。根据“Before we run or jog, we must do warm-up exercises.”可知,在我们快跑或慢跑前,我们必须做热身运动。故选 D。
52.C 解析:细节理解题。根据“Before we play ball games or swim, it is better for us to do bending and stretching first. This kind of exercise is sometimes called 'warm-up exercise'.”可知,弯腰和伸展运动属于热身运动。故选 C。
53.C 解析:细节理解题。根据“Some people like weight lifting because it can make their bodies strong.”可知,人们喜欢举重,是因为举重可以使人们的身体强壮。故选 C。