改正在括号处注明（最后一处有两种改正方法）：
Mobile phones are being more (widely) used.They're light (in) weight and easy to carry,offering fast and convenient service for communication.The users use them for (making) phone calls,sending short messages and Internet-surfing.In (recent) years,mobile phones have become popular with (the?此处是不是打字有误?) families and friends,(去掉and) which,of course was convenient.However,I don't think it's good to do so.In spite of the (advantages) mentioned above,student users often waste a lot of time chatting on the phone in (their) spare time.Some even use them to cheat (in) exams.In addition,mobile phone bills cost students' parents (a) lot / (lots) of money. 改正在括号处注明（最后一处有两种改正方法）：
Mobile phones are being more (widely) used.They're light (in) weight and easy to carry,offering fast and convenient service for communication.The users use them for (making) phone calls,sending short messages and Internet-surfing.In (recent) years,mobile phones have become popular with (the?此处是不是打字有误?) families and friends,(去掉and) which,of course was convenient.However,I don't think it's good to do so.In spite of the (advantages) mentioned above,student users often waste a lot of time chatting on the phone in (their) spare time.Some even use them to cheat (in) exams.In addition,mobile phone bills cost students' parents (a) lot / (lots) of money.