根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。
Cell Phones: Hang Up or Keep Talking?
Millions of people are using cell phones today. In many places it is actually considered unusual not to use one. ____ They find that the phones are more than a means of communication----having a mobile phone shows that they are cool and connected.
The explosions around the world in mobile phone use make some health professionals worried. Some doctors are concerned that in the future many people may suffer health problems from the use of mobile phones. In England, there has been a serious debate about this issue. Mobile phone companies are worried about the negative publicity of such ideas. ____
On the other hand, why do some medical studies show changes in the brain cells of some people who use mobile phones? Signs of change in the tissues of the brain and head can be detected with modern scanning(扫描)equipment. In one case, a traveling salesman had to retire at a young age because of serious memory loss. ____ He would often forget the name of his own son. This man used to talk on his mobile phone for about six hours a day, every day of his working week, for a couple of years. His family doctor blamed his mobile phone use, but his employer's doctor didn't agree.
____ The answer is radiation. High-tech machines can detect very small amounts of radiation from mobile phones. Mobile phone companies agree that there is some radiation, but they say the amount is too small to worry about.
As the discussion about their safety continues, it appears that it's best to use mobile phones less often. ____ Use your mobile phone only when you really need it. Mobile phones can be very useful and convenient, especially in emergencies. In the future, mobile phones may have a warning label that says they are bad for your health. So for now, it's wise not to use your mobile phone too often.
A. Use your regular phone if you want to talk for a long time.
B. They will possibly affect their benefits.
C. In many countries, cell phones are very popular with young people.
D. He couldn't remember even simple tasks.
E. What do the doctors worry about?
F. They say that there is no proof that mobile phones are bad for your health.
G. What is it that makes mobile phones potentially harmful?
