题目内容：

    You’ve likely noticed them by now. School buses are back on the street packed with students. Many of those kids step off the buses with a potential health danger over their shoulder — a backpack filled with homework.

Backpacks come in all shapes, sizes and colors. It is a fun way for any girl or boy to express their styles. Some are simple, some covered with cartoon characters, many equipped with special compartments for every tool a student needs, like pencils, notebooks and books.

Yes, they are practical, but a heavy backpack can injure muscles and joints. Wearing a backpack incorrectly can lead to severe back, neck and shoulder pain, as well as posture problems. When a backpack filled with books is placed on a boy or girl’s shoulders incorrectly, the force of the weight can pull the child backward, so the child may bend their hips forward or arch their back.

Pay attention to detail when selecting a backpack; choose one that is equipped with a comfortable back, waist and wide shoulder straps. Narrow straps can dig into a child’s shoulders and affect circulation and nerves. The heavy load danger is not just for kids 12 and under. Middle and high school are at risk, too. They are carrying heavier books home daily.

Luckily, back pain created by backpacks is preventable. Parents should talk to their kids about lightening the load. You can even use a bathroom scale. The backpack should not weigh more than 10 percent to 15 percent of your child’s weight. If your child weighs 80 pounds, the pack should not weigh more than 8 to 12 pounds. If your child weighs 140 pounds, the pack should not be heavier than 21 pounds. Most importantly, if your child talks about numbness or weakness in the arms or legs, contact a physician.

1.What do students’ backpacks reflect according to paragraph 2?

A.Their hobbies. B.Their styles.

C.Their characters. D.Their needs.

2.What is paragraph 3 mainly about?

A.Students’ heavy loads. B.Wearing backpacks incorrectly.

C.Dangers of heavy backpacks. D.Weight of heavy backpacks.

3.Which backpack is more suitable for a child weighing 100 pounds?

A.With wide shoulder straps weighing about 10 pounds.

B.With narrow shoulder straps weighing 16 pounds.

C.With wide shoulder straps weighing 20 pounds.

D.With narrow shoulder straps weighing 15 pounds.

4.Who are the intended readers of the text?

A.Children. B.Doctors.

C.Teachers. D.Parents.