Can you imagine a world without the Internet？It’s surprising to think about it.
Now，China has more than 162 million Internet users，according to the China Internet Network Information Center.This is the second highest number of users in the world after theUnited States.Today，66% of Chinese "netizens"（网民）are teenagers."They spend about thirteen hours every week online，said Qian Hulin，an Internet expert（专家）.Doctor Song in Beijing Xuanwu Hospital said about 14%of Chinese netizens who were teens（十几岁）often spent over ten hours playing online games in a week.
The main reasons why teenagers surf the Internet are to search for information，to communicate with others and to have fun.On the Internet，teenagers can find out almost anything.And surfing the Internet can help students with their homework and widen their knowledge.
Li Dong，a teacher at No.41Middle School in Shijiazhuang，would like her students to use the Internet."When we talk in class，students who surf the Internet usually know more background information than the others”，she said.
Besides，people can use the Internet to write letters or stories and send e-mails.Many teens keep in touch with their friends online.It is cheaper than phoning somebody far away and also much quicker.

Which way is the cheapest and quickest to learn something about friends far away？（）