In addition, cell phone can lead to addiction and health problem. When I study in class, I will see some student chatting with their friends. This cause will make them addict. And I also think, using cell phone in class make student gets lower point. Furthermore, cell phones are very dangerous to the human body. A study by Swedish researchers, suggests the link between cell phone use and emergence of Alzheimer’s disease. Experiment was made on rats. “Cell phones damage key brain cells and could trigger the early onset of Alzheimer’s disease. Researchers have found that radiation from cell phone handsets damages areas of the brain associated with learning memory and movement.” Therefore, people shouldn’t sleep with their cell phone beside them, and it is better if you switch off your cell phone before sleeping.