Are you carrying too much on your back to school？You're not alone.Back experts （专家） in the United States are worried that young students are having back and neck problems as a result of carrying too much in their schoolbags.
   "It hurts my back when I run，" said Oberlin Reyes，a student in Virginia. "It's hard to go up the stairs with my schoolbag，because it's too heavy."
   Oberlin is among students whose schoolbags were weighed for a week in a recent study.
   They had regular schoolbags with two straps （带子） to carry them，but a number of students with heavy loads had switched to rolling schoolbags （which have wheels and can roll on the ground）.
   Shirley Park，whose schoolbag weighed 10 kilograms，said she changed to a rolling schoolbag because she was starting to have back pain.
   How much is too much？Experts say students should carry no more than 10 to 15 percent of their own body weight.
   A few students had one suggestion to lighten the load：Less homework.

（1）According to some experts，carrying too much in the schoolbags may

C

C

.
A．lead to overweight problems
B．cause students to hate school
C．do harm to students' health
D．result in a sharp pain in the leg and neck
（2）What can we learn about Oberlin Reyes？

B

B

A．His schoolbag weighs about 10 kilograms.
B．His schoolbag is a regular one with two straps.
C．He is in charge of a recent study.
D．He doesn't like running or climbing the stairs.
（3）The expression "switched to" in Paragraph 4 perhaps means

A

A

.
A．started to use
B．picked up
C．given up
D．stopped buying
（4）According to the passage，it's better for a student of 40 kilograms to carry a schoolbag of

D

D

at most by the words of the experts.
A．9 kg
B．8 kg
C．7 kg
D．6 kg
（5）According to the passage，we know

D

D

.
A．rolling schoolbags are more popular
B．students don't have to do too much homework
C．schoolbags without wheels are bad for students
D．too much homework makes the students increase the studies load