Are you carrying too much on your back at school? You’re not alone. Back experts in the Un

Are you carrying too much on your back at school? You’re not alone. Back experts in the United States are worried that young students are having back and neck problems as a result of carrying too much in their backpacks (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 backpack,because it’s too heavy,”
Oberlin was among students whose backpacks were weighed for a week in a recent study.
They had regular backpacks with two straps(带子)to carry them, but a number of students with heavy loads had switched to rolling backpacks (which have wheels and can roll on the ground).
Shirley Park, whose backpack weighed 10 kilograms,said she changed to a rolling backpack 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.
P.S.( 附)Doctor’s suggestion:
1 Lighten the load. Clean out binders(活页材料)and take home only the books you need that night.
2 Wide straps are better. They send out the weight over your shoulders more evenly(均匀)。 And be sure to wear both straps rather than hanging the pack over one shoulder.
3. Pack smart. The heavier things should be packed closed to the back.
4.Bend both knees when you pich up the pack ,and don’t just bend over at the waist.(腰)
【小题1】“ ”is the main idea of the text.
A The problem of backpacks is worth studying.
B The problem made by heavy backpacks
C What is the best backpack for a student.
D How to make students’backpacks light.
【小题2】According to Oberlin Reyes and Shirley Park, we know .
A students have to do too much homework
B students have to carry several backpacks
C backpacks without wheels are bad for students
D too much homework leaves students no free time
【小题3】The expression “switched to” in the text perhaps means .
A started to use B turned to C caught up D used for
【小题4】According to the passage ,it’s better for a student of 40 kilograms to carry a backpack of at most by the words of experts.
A 10kg B 8kg C 6kg D 7kg
【小题5】 If students follow the doctor’s suggestions they .
A may lighten their backpacks
B can learn how to help themselves
C may feel their backpacks are lighter
D will know how to wear backpacksD

(答案→)D 解析：【小题1】本文主要谈论了美国学生们的书包里所背的东西太多太重，如何才能使学生们的书包减轻，故本题选D。【小题2】本文中有一句为A few students had one suggestion to lighten the load:less homework.所表示的含义为学生有太多的作业从来导致书包太重，故本题选A。【小题3】本文第三段最后一句为a number of students with heavy loads had switched to rolling backpacks 所表示的含义许多背着很重东西的学生开始使用可以在地上转动的书包，所以“switched to”的含义为开始使用的含义，故本题选A。【小题4】本文中有一句为Experts say students should carry no more than 10 to 15 percent of their own body weight.，所表示的含义为学生们所背的东西重量不要超过自身重量的百分之10到15，所以40公斤的学生背的东西重量不要超过6公斤，故本题选C。【小题5】本文最后提到了医生的4点减轻学生负荷的建议，如果学生采取，他们可能会减轻他们的书包重量，故本题选C 。

这个问题的回答的对