参考答案：

　　BAEFC

　　完形填空

　　Cell Phone Lets Your Secrets Out

　　Your cell phone holds secrets about you.Besides the names and numbers that you've programmed into it, ______traces____(51) of your DNA linger (遗留) on thedevice according to a new study

　　DNA is genetic (遗传的)material _____that_____ (52) appears in every cell. Like your fingerprint, yourDNA is _____unique______ (53) to you——unless you have an identical twin. Scientiststoday analyze DNA in blood, saliva (唾液), orhair left ____behind_______ (54) at the scene of a crime. The results oftenhelp detectives identify ____criminals______ ..........