题目内容
—________is it from your school to the museum?
—About half an hour by car.
A.How long B.How far C.How often D.How much
计算高手系列答案Mobile phone history
Not long ago, mobile phones were used mainly by business people and government officers in society. In the US, mobile phone users were about 340,000 in 1985. Now there are 205 million mobile phones users in the US. Studies also show that over 50 percent of children in the US own their own personal mobile phones. The mobile phones explosion(激增) has led to a huge number of waste phones. The number of mobile phone users has also increased throughout the world. In the middle of 2005, the number of total users jumped to 2.4 billion worldwide.
Mobile phone waste
When people throw their mobile phones away, they usually end up in the open air. Mobile phones include some materials like lead, mercury and cadmium。 They can go into public drinking water and food and do harm to people’s health. About 75 percent of mobile phone users don’t know their phones away. Instead, they prefer to keep the waste ones sitting around the house as they are not worth very much. People are also afraid that others may know their information if they sell their waste phones. Less than 20 percent of them are recycled each year.
Benefits of recycling mobile phones
Mobile phones have valuable materials inside. The most valuable material is gold, which is used in the phone circuit boards. Recycling can reduce greenhouse gas emissions(排放物) and keep natural resources like gold. If all of the waste phones in the US are recycled, it will save enough energy to offer over 194,000 US families electricity(电) for one year.
How mobile phone recycling works
Many people do not know how mobile phone recycling works. One method of recycling mobile phones is to take the working parts of broken phones, then combine(使结合) them with the working parts of other used mobile phones to make one ready-to-use mobile phone. Another method of mobile phone recycling is to melt(融化) down and separate parts of the phone in order to get the valuable natural resources, such as gold and platinum. Plastic and glass can also be recycled from used mobile phones.
The used mobile phones | |
Mobile phone history | ●Compared with the condition in 1985, there are1. mobile phone users at present. ●More than2. of the children in America have their own personal mobile phones. ●The mobile phone explosion has3. a huge number of waste phones. |
Mobile phone waste | ●Some materials, such as lead, mercury and cadmium in the mobile phones are4. to people’s health. ●Three-quarters of the users prefer to keep the waste phones sitting around the house5. of throwing them away. |
Benefits of recycling | ●Some materials are of great6.. They can be used again. ●It can7. plenty of electricity for American families if the waste phones are recycled. |
How recycling8. | ●One way is to join working parts of9. or used phones together. ●10. way is to melt down and separate parts of the phones to get the valuable natural resources. |