INTRODUCTION
BACKGROUND OF THE STUDY A mobile phone (also called mobile, cellular telephone, or cell phone) is an electronic device used for two-way radio telecommunication over a cellular network of base stations known as cell sites. Mobile phones differ from cordless telephones, which only offer telephone service within limited range through a single base station attached to a fixed land line, for example within a home or an office. Today, cell phones are the most popular tool for communication in modern life. They become a “must have” that everybody cannot live without. Although cell phones have many positive effects for human life, there are also some negative effects.
First, all cell phones are convenient and comfortable for users since they are small and light; therefore people can carry them every time and everywhere. Secondly, cell phones have been developing a lot of new thing, which contain a lot of additional features: alarm, calendar, camera, Internet, etc. Consumers can use a lot of functions at the same time; they can read stories, listen to music, connect to Internet, and watch videos whenever and wherever they want with cell phones. Third, cell phones help people stay connect with each other regardless of the distance. If they want to talk to their friends, they just need to send messages or make an instant call in order to share emotions, sadness or happiness; which make they might feel better and have more pleasures. Cell phones do make people’s relationship become closer. In addition to being a telephone, modern mobile phones also support many additional services, and accessories, such as SMS (or text) messages, e-mail, Internet access, gaming, Blue-tooth and infrared short range wireless communication, camera, MMS messaging, MP3 player, radio and GPS. Along with their books and school supplies, many students make their daily trip to school with their trusty mobile phone. These pocket-sized tools can