Cellphones or not?

As our society develpos,more and more middle school students take cellphones to school.Is this good or not? 　
　Many American parents think cellphones can let them know where their children are and help them to handle emergencies.But most students just regard the cellphone as an entertainment.Some students answer the cellphone even in class.And it really disturbs the teacher and other students. 　
　As a middle school student,I think going to school with cellphone is wrong.Firstly,schools supply the public phone,so it is unnecessary ti use cellphones in school.Secondly,if you have a cellphone,you have to spend much money on it.Thirdly,answering the cellphone in class will influence the duties.Fourthly,there is an radiation when we use cellphone,it is harmful to our health. 　
　In a word, taking cellphone to school is wrong.It should be forbidden.So why not stop taking cellphones to school from now on?