题目内容：
共用题干Cell Phone Lets Your Secret Out
Your cell phone holds secrets about you.Besides the names and _____________(51)that you've pro-
grammed into it,traces of your DNA linger on the device,according to a new study.
DNA is genetic material that______________(52)in every cell.Like your fingerprint,your DNA is unique
to you一 _____________（53)you have an identical twin.Scientists today routinely analyze DNA in blood,
saliva,or hair left _____________(54)at the scene of a crime.The results often help detectives identify
_____________(55)and their victims.Your cell phone can reveal more about you _____________(56)you might
think.
Meghan J.McFadden,a scientist at McMaster University in Hamilton,Ontario,heard about a crime in
which the suspect bled onto a cell phone and later dropped the______________(57).This made her wonder
whether traces of DNA lingered on cell phones even when no blood was involved.______________(58)she and
colleague Margaret Wallace of the City University of New York analyzed the flip-open phones of 10 volun-
teers.They used swabs to collect______________(59)traces of the users from two parts of the phone:the
outside,where the user holds it,and the______________(60),which is placed at the user's ear.
The scientists scrubbed the phones using a solution made mostly______________(61)alcohol.The aim of
washing was to remove all detectable traces of DNA.The owners got their phones______________(62)for
another week.Then the researchers collected the phones and repeated the swabbing of each phone once
more.
The scientists discovered DNA that _____________(63)to the phone's speaker on each of the phones.
Better samples were collected from the outside of each phone,but those swabs also picked up DNA that be-
longed to other people who had apparently also handled the phone.______________(64),DNA showed up even
in swabs that were taken immediately after the phones were scrubbed.That suggests that washing won't remove
all traces of evidence from a criminal's device.So cell phones can now be added to the
______________(65)of clues
that can clinch a crime-scene investigation.
_________(54)
A:about
B:in
C:for
D:behind
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