Cellphonesareveryusefulandthey'regreatfun.Butcellphonesdohaverisks.Ifyouhaveone,itisnecessarytounderstandtheserisks,andlearn__11__enjoyyourphonesafely.__12__canbeawonderfulwaytokeepintouchwithyourfriends.Butbadpeoplecanalsosendmessages.Ifyoureceivearudeorterrifyingmessage,donotreplyorforward(转发)it.__13__,
savethemessageandshowittoyourteachersorparents.Ifyoureceiveamessagesayingthatyou__14__abigprize,don'tbelieveit.Sendingpicturesfromacellphoneisfast,easyandfun.Butmakesureyousendonlypicturesthatyouwouldn'tmindotherpeople__15__.Andyouaremorelikelytohaveanaccidentifyoutrytouseyourcellphonewhile__16__theroad.Therearecarsandbusestowatchoutfor!Hangupyourcellphone__17__youwalk.Withyourparents'help,youcankeepyourcellphone's__18__,youwon'thavetoworryaboutreceivingunwantedcallsormessages!Remembernottotalkonthecellphonetoooftenortoolong.Yourparentswillbe__19__ifyouspendtoomuchmoney.__20__yourcellphonewhenyousleep.Thesoundsofrubbishmessagesmaywakeyouup.(B)11.A.howB.howtoC.whatD.whatto(C)12.A.SendmessagesB.UsecellphonesC.SendingmessagesD.Us