题目内容：

Are you carrying too much on your back at school? I’m sure lots of children of your age will say “Yes”. Not only the students in China have this problem, but children in the United States also have heavy school bags.

Doctors are starting to worry about young students’ back and neck because their school bags are too heavy for them.

“It’s hard for me to go upstairs with my heavy bag,” said Rick Hammond, an ll-year-old student in the USA.

Rick is among students who have school bags with two straps(带子),and many other students choose rolling(有滚轮的) bags.

But even with rolling bags ,getting upstairs is still a problem for children .Doctors say students should carry no more than 10% to 15% of their own body weight (重量)。

Scott Bautch, a back doctor, said children under Grade 4 should carry no more than 10% of their weight and older children shouldn’t stay with over 15% , because their bodies are still growing.

Teachers and parents should do some things to help children. And the best answer is to have less homework!

1.From the passage we cam know that        .

A．only children in China carry too heavy school bags.

B．children in other countries don’t carry too heavy bags.

C．both children in China and the USA carry too heavy school bags.

D．only children in the USA carry too heavy school bags.

2.Children feel it hard for them to go upstairs because          .

A．they are too young.

B．their school bags are too heavy.

C．they are too heavy.

D．their parents don’t always go upstairs with them.

3.If a child carries a heavy school bag,        .

A．his back and neck may be hurt.

B．his head and arms may be hurt .

C．his hands may be hurt .

D．his feet may be hurt .

4.According to the doctor, Scott Bautch, if a child in Grade 5 weighs about 30 kilos, the school bag he carries should not be over          .

A．5 kilos            B．3 kilos            C．5.5 kilos           D．4.5 kilos

5.Some students think the best answer to this problem is that          .

A．they should have a little homework to do after they get home

B．their teachers had getter not ask them to do any homework

C．they should only take home the books they will read that night.

D．They should use thin books instead of thick ones.