Cell phones are an integral part of our society and their main use is communication. They keep students in touch with the rest of the world by giving them the power to interact with it. In my day, if you forgot your lunch, you were at the mercy of the office calling home for you. Now, students have the ability to solve their own problems and handle certain emergencies on their own.
Cell phones also allow students to keep in touch with students at other schools or friends that don’t go to school. While not an educational benefit directly, better relationships can lead to higher self-esteem and reduce isolation, which is good for everybody. In the same way, camera phones allow students to capture the kinds of memories that help build a solid school culture, and, in some cases, can act as documentation of misbehavior in the same way that store cameras provide evidence and deter bad behavior.
Academically, the cell phone can act as to record video of a procedure of explanation that may need to be reviewed later. It could be used to record audio of a lecture, as well, for later review. And just imagine if classes could be easily taped for students who are absent? What if they could even be streamed and seen from home instantly?

There are a lot of disadvantages of living in a big city, air pollution is among (30) most serious problems. Firstly, air pollution comes from the factories in the city. Big cities attract a lot of both inside and outside investments, (31) the number of factories is increasing quickly. This makes the air extremely (32) by smoke from factories. Secondly, that there are too many means also makes this problem worse. Exhaust from cars, motorbikes is one of the factors (33) make the air polluted. To conclude, air pollution, which expects to make more and more people get many serious (34) such as lung cancer, tuberculosis and so on, is a big drawback of city life.