2020年职称英语考试《理工类》考试共65题，分为单选题和多选题和判断题和计算题和简答题和不定项。小编每天为您准备了5道每日一练题目（附答案解析），一步一步陪你备考，每一次练习的成功，都会淋漓尽致的反映在分数上。一起加油前行。

1、Cell Phone Lets Your Secret OutYour 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 ______ 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 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. Surprisingly, 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.criminals

B.people

C.men

D.policemen

正确答案:A

答案解析:根据上下文的理解，研究结果是用来帮助侦探识别罪犯和受害人的，B、C、D都不能表达这一层意思。

2、Mary rarely speaks to Susan.【单选题】

A.slowly

B.seldom

C.weakly

D.constantly

正确答案:B

答案解析:玛丽很少和苏珊说话。本题难度不大，干扰项干扰不强。rarely和seldom都可指“很少地”，其他项和答案意义差异较大，最佳答案是B。

3、They didn\'t want anyone to know about their romance. 【单选题】

A.adventure

B.mystery

C.poem

D.love

正确答案:D

答案解析:romance:浪漫史，他们的浪漫史也就是他们的love; adventure：冒险；mystery：神秘、奥秘；poem:诗歌。

4、We\'re happy to report that business is booming this year.【单选题】

A.risky

B.successful

C.failing

D.open

正确答案:B

答案解析:我们很高兴地向大家报告今年业绩红火。本题难度不大，booming指“景气，繁荣”，和successful“成功的”是近义词，A项指“冒险的”，C项指“衰退的”，D项指“开放的”，都不合句意，最佳答案是B。

5、Weaving with LightIn the Sierra Madre mountain range of west central Mexico, the native Huichol people live much the way their ancestors did-without electricity. That\'s because it\'s too expensive to string power lines to the remote mountain areas where they live. To help support themselves, the Huichol create beautiful artwork. They sell their art in cities hundreds of miles away from their villages. And without electricity, at home or on the road, they can only work during daylight hours. When it gets dark, they must stop whatever they\'re doing.Now, a team of scientists, designers and architects is using new technologies to provide the Huichol with light after the sun sets. The scientists technique involves weaving tiny electronic crystals into fabrics that can be made into clothes, bags, or other items.By collecting the sun\'s energy during the day, these lightweight fabrics provide bright white light at night. Their inventors have named the fabrics "Portable Lights," Portable Lights have the potential to transform the lives of people without electricity around the world, says project leader Sheila Kennedy."Our invention," Kennedy says, "came from seeing how we could transform technology we saw every day in the United States and move it into new markets for people who didn\'t have a lot of money."At the core of Portable Light technology are devices called high - brightness light - emitting diodes, or HB LEDs. These tiny lights appear in digital clocks, televisions and streetlights.LEDs are completely different from the light bulbs. Most of those glass bulbs belong to a type called incandescent lights. Inside, electricity heats a metal coil to about 2,200 degrees Celsius. At that temperature, bulbs give off light we can see.Ninety percent of energy produced by incandescent lights, however, is heat and invisible. With all that wasted energy, bulbs burn out quickly. They are also easily broken.LEDs, on the other hand, are like tiny pieces of rock made up of molecules that are arranged in a crystal structure. When an electric current passes through an LED, the crystal structure produces light. Unlike incandescent bulbs, they can produce light of various colors. Within an LED, the type of molecules and their particular arrangement determines what color is produced.The central part of the Portable Lights technology is ______.【单选题】

A.glass bulbs

B.digital clocks

C.incandescent lights

D.HB LEDs

正确答案:D

答案解析:本题有一定难度，关键在吃透句意，答案依据比较明显，带着题干信息词回文章定位，答案依据主要在文章第五段第一句：At the core of Portable Light technology are devices called high - brightness light - emitting diodes or HB LEDs。其中core和题干里的central part是同义词，回来看选项，D项和原文句意相符，答案是D。