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 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 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 ______ 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.was given

B.belonged

C.was owned

D.became

正确答案:B

答案解析:该句要表达的意思应该是：科学家在每一个手机上发现了属于手机拥有者的DNA。belong to是固定搭配，意思是：属于。A不符合句义，C和D不符合语法。

2、Radiocarbon DatingNowadays scientists can answer many questions about the past through a technique called radiocarbon (放射性碳), or carbon - 14 dating. One key to understanding how and why something happened is to discover when it happened.Radiocarbon dating was developed in the late 1940s by physicist Willard F. Libby at the University of Chicago. An atom of ordinary carbon, called carbon -12, has six protons (质子) and six neutrons (中子) in its nucleus (原子核). Carbon - 14, or C - 14, is a radioactive, unstable form of carbon that has two extra neutrons. It returns to a more stable form of carbon through a process called decay (衰减). This process involves the loss of the extra neutrons and energy from the nucleus.In Libby\'s radiocarbon dating technique, the weak radioactive emissions(放射)from this decay process are counted by instruments such as a radiation detector and counter. The decay rate is used to determine the proportion of C -14 atoms in the sample being dated.Carbon - 14 is produced in the Earth\'s atmosphere when nitrogen(氮) - 14, or N - 14, interacts with cosmic rays (宇宙射线). Scientists believe since the Earth was formed, the amount of nitrogen in the atmosphere has remained constant. Consequently, C -14 formation is thought to occur at a constant rate. Now the ratio of C -14 to other carbon atoms in the atmosphere is known. Most scientists agree that this ratio is useful for dating items back to at least 50,000 years.All life on Earth is made of organic molecules (分子) that contain carbon atoms coming from the atmosphere. So all living things have about the same ratio of C -14 atoms to other carbon atoms in their tissues (组织). Once an organism (有机体) dies it stops taking in carbon in any form, and the C -14 already present begins to decay. Over time the amount of C - 14 in the material decreases and the ratio of C - 14 to other carbon atoms goes down. In terms of radiocarbon dating, the fewer C -14 atoms in a sample, the older that sample is.The radiocarbon dating technique is only about 40 years old.【单选题】

A.Right

B.Wrong

C.Not mentioned

正确答案:B

答案解析:本题有一定难度，需要认真寻找答案依据。主要答案依据在文章第二段第一句：Radiocarbon dating was developed in the late 1940s谈到放射性碳测定法源于20世纪40年代，显然，早就超过了40年历史，所以本题错误，答案是B。

3、A research center has been set up in this country.【单选题】

A.praised

B.established

C.reformed

D.criticized

正确答案:B

答案解析:题干大意：在这个国家已经建起了一个研究中心。画线词set up：建立。选项中，establish：建立，可互换而不改变句子。praise：表扬。如：Praise and positive reinforcement are an important part of the Matsushita philosophy. 表扬和正面帮助是三菱哲学思想的重要组成部分。criticize：批评。如：Some education experts criticized the program because its teachers get only five weeks of training before they start teaching. 有的教育界权威批评这个项目，因为它的老师在执教之前只得到仅仅五周的培训。reform：改革。如：The trouble is they have never succeeded at tax reform. 糟糕的是他们没有成功地进行税收改革。

4、We were astonished to hear that their football team had won the champion. 【单选题】

A.amazed

B.amounted

C.amused

D.approached

正确答案:A

答案解析:astonish和amaze同义，使惊讶；amount:总计；amuse:使愉快；approach:接近、方法、途径。

5、Science Fiction1 Amongst the most popular books being written today are those that are usually classified asscience fiction. Hundreds of titles are published every year and are read by all kinds of people. Furthermore, some of the most successful films of recent years have been based on science fiction stories. 2 It is often thought that science fiction is a fairly new development in literature, but its ancestors can be found in books written hundreds of years ago. These books were often concerned with the presentation of some forms of ideal society, a theme that is still often found in modern stories. 3 Most of the classics of science fiction, however, have been written within the last hundred years. Books by writers such as Jules Verve and H. G Wells, to mention just two well known authors, have been translated into many languages. 4 Modern science fiction writers don\'t write about men from Mars or space adventure stories. They are more interested in predicting the results of technical developments on society and the human mind; or in imagining future worlds that are a reflection of the world that we live in now. Because of this their writing has obvious political undertones (涵义). 5 In an age where science fact frequently overtakes (超过) science fiction, the writers may find it difficult to keep ahead of scientific advances. Those who are sufficiently clear-sighted to see the way we are going, however, may provide a valuable lesson on how to deal with the problems which society will inevitably face as it tries to master its new technology. Paragraph 4____【单选题】

A.A Fairly New Development

B.Classics of Science Fiction

C.Difficulty in Keeping ahead of Scientific Advances

D.Origins of Science Fiction

E.Themes of Modern Science Fiction

F.SuccessfulFilms

正确答案:E

答案解析:第4段的起始句说现代科幻小说家们的兴趣不在火星和太空，这其实只是后面句群的铺垫，是为了引起读者对后文的关注，接下来的句子才说出他们真正的兴趣所在。当作家把他们感兴趣的东西写进小说中时，这些也就构成了现代科幻小说的主题，故选E。