Are you carrying too much on your back to school？You're not alone.Back experts （專家） 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 （帶子） 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）Students in America carry too much on their back to school，don't they？

Yes，they do.

Yes，they do.

（2）What problems may cause when students carry too much in the schoolbags ？
 

It may cause back and neck problems.

It may cause back and neck problems.

（3）Why did Shirley Park switch regular schoolbags to a rolling schoolbag ？
 

Because she was starting to have back pain.

Because she was starting to have back pain.

（4）What does the expression "switched to" in Paragraph 4 perhaps mean？
 

It means "changed to".

It means "changed to".

（5）According to the experts，If a student weighs 40 kilograms，how many kilograms can he carry a schoolbag at most ？

6 kilograms.

6 kilograms.

（6）What are your suggestions to lighten the load？ （At least 2 suggestions）

Student can put some books in their own book shelves at school.Student can finish some homework at school.

Student can put some books in their own book shelves at school.Student can finish some homework at school.