职称英语考试《理工类》章节练习题精选及
答案0517-100
1、Cell Phone Lets Your Secret Out
Your cell phone holds secrets about you. Besides the names and numbers that you've programmed into it, traces of your DNA linger on the device, according to a new study.
DNA is genetic material that appears in every cell. Like your fingerprint, your DNA is unique to you- because you have an identical twin. Scientists today routinely analyze DNA in blood, saliva, or hair left behind at the scene of a crime. The results often help detectives identify criminals and their victims. Your cell phone can reveal more about you than 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 device. This made her wonder whether traces of DNA lingered on cell phones even when no blood was involved. So she and colleague Margaret Wallace of the City University of New York analyzed the flip open phones of 10 volunteers. They used swabs to
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collect invisible traces of the users from two parts of the phone: the outside, where the user holds it, and the speaker, which is placed at the user's ear.
The scientists scrubbed the phones using a solution made mostly of alcohol. The aim of washing was to remove all detectable traces of DNA. The owners got their phones back for another week. Then the researchers collected the phones and repeated the swabbing of each phone once more.
The scientists discovered DNA that belonged to the phone's speaker on each of the phones. Better samples were collected from the outside of each phone, those swabs also picked up DNA that belonged to other people who had apparently also handled the phone. ______, 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 list of clues that can clinch a crime scene investigation. 【单选题】
A.Generally
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B.Surprisingly
C.Disappointedly D.Shortly
正确答案:B
答案解析:最后一段的第一和第二句告诉我们手机经过清洗后仍然有微量DNA出现。所以这里要用surprising这个副词，表示令人惊讶。
2、Breastfeeding Can Cut Cardiovascular Risk
Breastfeeding can reduce the risk of a heart attack or stroke later in life and could prevent hundreds of thousands of deaths each year, researchers said on Friday.
Babies who are breastfed have fewer childhood infections and allergies and are less prone to obesity. British scientists have
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职称英语考试《理工类》章节练习题精选及答案0517-100
