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.
Many children like mobile phones because they think mobile phones are _________.

A．cool

B．small

C．cheap

D．their toys

Many of the mobile phone users in the U.S. are ___________.

A．girls

B．boys

C．scientists

D．children

Some scientists think mobile phones aren’t _________ for users health. They causes some kinds of cancer

A．bad

B．good

C．wrong

D．helpful

The underlined word “threaten” in the passage means ____________.

A．威胁.

B．担心

C．治疗

D．证实

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