2021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。小编为您整理完形填空分析5道练习题，附答案解析，供您备考练习。

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 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 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 ______ 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.of

B.up

C.on

D.into

正确答案:A

答案解析:be made of是固定搭配，意即：由……制成。a solution made mostly of alcohol：一种主要由酒精制成的溶液。

2、One Good Reason to Let Smallpox LiveIt\'s now a fair bet that we will never see the total extinction (灭绝) of the smallpox (天花) virus. When smallpox was completely got rid of in the world, scientists wanted to destroy the killer virus in the last two labs, one in the US and one in Russia. They asked: If smallpox has truly gone from the planet, what point was there in keeping these reserves?In reality, of course, it was naive to imagine that everyone would let go of such a powerful potential weapon. Undoubtedly several nations still have a few vials (小药瓶). And the last "official" stocks of live Virus bred mistrust of the US and Russia, _____ no obvious gain.Now American researchers have found an animal model of the human disease, opening the way for tests on new treatments and vaccines(疫苗). So once again there\'s a good reason to the virus, just in keep the disease puts in a reappearance.How do we case with the mistrust of the US and Russia? deal. Keep the virus Simple international support in a well - guarded UN laboratory that\'s open to all countries. The US will object, of course, just as it with a multilateral (多边的) approach to just about everything. But it doesn\'t mean the idea is rejects. If the virus is useful, then let\'s wrong it the servant of all humanity make not just a part of it.【单选题】

A.in

B.for

C.at

D.of

正确答案:B

答案解析:本题有一定难度，考查for的用法，for除了做介词外，还可做连词，表示“因为”，文章此处是说“……因为没有获得明显的收获”，答案是B。

3、What Is the Coolest Gas in the Universe?What is the coldest air temperature ever recorded on the Earth? Where was this low temperature recorded? The coldest recorded temperature on Earth was - 91℃, which occurred in Antarctica (南极洲) in 1983.We encounter an interesting situation when we discuss temperatures in space.Temperatures in Earth orbit actually range from about +120℃ to - 120℃. The temperature depends upon whether you are in direct sunlight or shade. Obviously, -120℃ is colder than our body can safely endure. Thank NASA science for well, de signed space suits that protect astronauts from these temperature extremes.The space temperatures just discussed affect only our areal of the solar system. Obviously, it is hotter closer to the Sun and colder as we travel away from the Sun. Astronomers estimate temperatures at Pluto are about - 210℃. How cold is the lowest estimated temperature in the entire universe? Again, it depends upon your location. We are taught it is supposedly impossible to have a temperature below absolute zero, which is - 273℃, at which atoms do not move. Two scientists, whose names are Cornell and Wieman, have successfully cooled down a gas to a temperature barely above absolute zero. They won a Nobel Prize in Physics in 2001 for their work, not a discovery, in this case.Why is the two scientists\' work so important to science?In the 1920s, Satyendra Nath Bose was studying an interesting theory about special light particles we now call photons (光子). Bose had trouble convincing other scientists to believe his theory, so he contacted Albert Einstein. Einstein\'s calculations helped him theorize that atoms _____ behave as Bose thought—but only at very cold temperatures.Scientists have also discovered that ultra - cold(超冷) atoms can help them make the world\'s atomic clocks even more accurate. These clocks are so accurate today they would only lose one second every six million years! Such accuracy will help us travel in space because distance is velocity times time 4 ( d = v×t). With the long distances involved in space travel, we need to know time as accurately as possible to get accurate distance.【单选题】

A.would

B.will

C.must

D.need

正确答案:A

答案解析:本题有一定难度，考查虚拟语气和时态一致的用法，干扰项有一定的干扰。根据上下文逻辑，文章此处是说“爱因斯坦的计算帮助Bose理论成立，即原子会象原来他设想的那样运行”，此处只是表示理论成立，而不等于是经过验证的科学事实，所以要用假设的语气，此外整个句子都是用的过去时态，因此答案是A。

4、Seeing Red Means Danger AheadThe color red often means danger and by paying attention, accidents can be prevented. In the future, the color red also may help prevent danger at construction sites. Thanks to new work by engineers, bridge supports or other kinds of materials, could one day contain a color - changing material. It will turn red before a structure collapses or falls apart.The secret _____ the color - changing material is a particular type of molecule (分子). A molecule is a group of atoms (原子) held together by chemical bonds. Molecules come in all shapes and sizes and make up everything you can see, touch or feel. How a molecule behaves depends on what kinds of atoms it contains and how they\'re held together.When a polymer (聚合物) containing a color - changing molecule called a mechanophore (机械响应性聚合物) is about to break, it produces a color. When a polymer with mechanophore molecules becomes "injured" or weak, one of the mechanophore bonds breaks and the material turns red. "It\'s a really simple detection method," says Nancy Sottos, one of the scientists who worked on the project. Sottos and her team tested the color - changing polymers in their lab. The test results proved encouraging.There is a way to get rid of the red color light. When a bright light is shone on the mechanophore, the broken bond is fixed and the red color disappears. Thus "self - healing" may be a problem for engineers. They need to use the color - changer in big construction projects that will be outside, under sunlight. And sunlight will make the mechanophore\'s warning system useless.Sottos and her fellow scientists still have a lot of work to do before the color - changing molecules can be used outside the lab.【单选题】

A.on

B.behind

C.under

D.down

正确答案:B

答案解析:本题有一定难度，干扰项干扰较大，考查介词behind的用法，文章此处是说，“材料颜色可以变化其背后的秘密是……”，只有behind可以表示“背后的”意思，答案是B。

5、Seeing Red Means Danger AheadThe color red often means danger and by paying attention, accidents can be prevented. In the future, the color red also may help ______ danger at construction sites. Thanks to new work by engineers, bridge supports or other kinds of materials could one day contain a color switching material. It will turn red before a structure collapses or falls apart. The secret behind the color switching material is a particular type of molecule. A molecule is a group of atoms held together by chemical bonds. Molecules come at all shapes and sizes, and make up everything. You can see, touch or feel. How a molecule behaves depends on what kinds of atoms it contains, and how they\'re held together. When a polymer (聚合物) containing a color switching molecule called a mechanophore (机械响应性聚合物) which is about to break, it produce a color. When a polymer with mechanophore molecules becomes "injured" or weak, one of the mechanophore bonds breaks and the material turns red. "It\'s a really simple detection method. "says Nancy Sottos, one of the scientists who worked on the project. Sottos and her team tested the color switching polymers in their lab. The test results proved encouraging. There is a way to get rid of the color light when a bright light is shone on the mechanophore. The broken bond is fixed and the red color disappears. This "self-healing" may be a problem for engineers. They need to use the color changer in big construction projects that will be outside in sunlight. And sunlight will make the mechanophore\'s warming system useless. Sottos and her fellow scientists still have a lot of work to do before the color switching molecules can be used outside the lab. 【单选题】

A.throw

B.prevent

C.create

D.keep

正确答案:B

答案解析:原文中用also may help，说明应填与上文prevent相似的词句。throw：投掷；create：创造；keep：保持，都与之不符，所以是prevent。