问题 解答题
(本题4分)某食品厂从生产的袋装食品中抽出样品20袋,检测每袋的质量是否符合标准,超过或不足的部分分别用正、负数来表示,记录如下表:
与标准质量的差值(单位:克)
-5
-2
0
1
3
6
袋    数
1
4
3
4
5
3
这批样品的平均质量比标准质量多还是少?若每袋标准质量为450克,则抽样检测的总质量是多少?
答案

-5

∴平均质量比标准质量多

总质量=450

 略

阅读理解

Many children think mobile phones are cool. They come in fun colors and let you talk with friends anytime and anywhere.

In the U.S., more than 90 million people use mobile phones. Many of these people are children. For children, mobile phones are more than phone calls. They are fashionable.

Most mobile phone users don’t think about the health problems caused(引起) by mobile phones. Some scientists say that mobile phones give off radiation(辐射) that might be bad for the users. One newest study shows that mobile phone radiation might raise(增加) a person’s chance of getting some kinds of cancer(癌症). Other scientists say mobile phones don’t’ threaten people’s health. They say that they have not found any link(联系) between phone use and cancer.

Scientists say that people can protect (保护) themselves from mobile phone radiation. One way is to use a headset(耳机). Or people can make shorter call.

小题1:Many children like mobile phones because they think mobile phones are _________.

A.cool

B.small

C.cheap

D.their toys小题2:Many of the mobile phone users in the U.S. are ___________.

A.girls

B.boys

C.scientists

D.children小题3:Some scientists think mobile phones aren’t _________ for users health. They causes some kinds of cancer

A.bad

B.good

C.wrong

D.helpful小题4:The underlined word “threaten” in the passage means ____________.

A.威胁.

B.担心

C.治疗

D.证实小题5:What should people do to protect themselves from mobile phone radiation?

A.Make longer calls

B.Use a headset

C.Make shorter calls

D.Both B and C

选择题