单选题 Passage Two
Too much eating. Too many unhealthy foods. Too many advertisements for food. Too little activity.
Different explanations are offered for America's weight problem--a problem increasingly shared by other countries. Almost one-fifth of American children and teenagers are overweight.
Schools have been urged to increase physical education, an important tool for public health. And many have. Yet now comes a study showing an increase in the number of injuries in physical education class. Injuries increased 150% between 1997 and 2007.
he study involved injuries treated in hospital emergency departments. Only 2% were serious. The researchers did not try to identify the causes of the increase, but they have some theories.
Lara McKenzie from Ohio State University was the lead researcher. She says one possibility is a decrease in the number of school nurses during the period they studied. For example, a 2004 study showed that the number of school nurses nationally failed to meet federal guidelines. Schools without a nurse on duty may be more likely to send an injured child to a hospital.
Another possible reason for more injuries is a change in the traditional idea of physical education. This "New PE." expands the kinds of sports that are taught. But activities that some schools offer now, like rock climbing walls and skateboarding, can also expand the risks, says Cheryl Richardson. She is with the National Association for Sport and Physical Education. Also, she says not all states require P.E. teachers to be specially trained. Untrained teachers could be less likely to recognize unsafe conditions.
Cheryl Richardson also points to one of the study's findings--that injuries are often the result of contact with a person or a structure. This tells her that the teachers were not giving each student enough space to move around safely.
Six activities produced 70% of all injuries: running, basketball, football, volleyball, soccer and gymnastics.
The researchers say larger class sizes are another possible reason for the increase in injuries. Larger classes can mean less supervision. The National Association for Sport and Physical Education says 20 to 30 students in a PE. class should be the limit.

单选题 Overweight problem is ______.
A. not common outside the United States of America
B. also a headache in other countries
C. caused by too many advertisements for food
D. neglected in many countries

单选题 The increase of physical education ______.
A. has reduced the number of overweight children
B. is the major cause of injuries of children in the U.S.
C. has more disadvantages than advantages
D. has caused more injuries in school

单选题 It is implied in Lara McKenzie's study that ______.
A. in the past some injuries were treated in school
B. school nurses are now more irresponsible
C. students don't have enough space to move around in school
D. schools lack funds in hiring school nurses

单选题 Which of the following is NOT included in the reasons for more injuries?
A. More dangerous activities.
B. Less specially trained teachers.
C. Less supervision.
D. More unhealthy food.

单选题 Which of the following activities has caused more injuries?
A. Rock climbing. B. Skateboarding.
C. Soccer. D. Swimming.

单选题 According to the researchers, the injury problem could be less serious if ______.
A. a P．E．class had fewer students
B. schools reduced the P．E． classes
C. schools reduced the outdoor activities
D. personal contacts were avoided