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。小编为您整理历年真题5道练习题，附答案解析，供您备考练习。

1、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 ｏｒon 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, ｏｒother 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 fｏｒpeople who didn\'t have a lot of money."At the core of Portable Light technology are devices called high - brightness light - emitting diodes, ｏｒHB 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 colｏｒis 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 ｏｒHB 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。

2、Obviously these people can be relied on in a crisis.【单选题】

A.lived on

B.depended on

C.believed in

D.joined in

正确答案:B

答案解析:显然这些人在危机关头值得依靠。本题有一定难度，考查的是基本意义，C项的干扰最大，有些考生因受汉语思维影响而选了C，rely on和depend on都有“依靠”意思，是近义词，常用过去式，C项believe in指“相信”，和答案意义有差异，最佳答案是B。

3、Radiocarbon DatingNowadays scientists can answer many questions about the past through a technique called radiocarbon (放射性碳), ｏｒcarbon - 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, ｏｒC - 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 detectｏｒａｎｄ　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, ｏｒN - 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 fｏｒdating 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.An atom of ordinary carbon has. six protons ａｎｄ　eight neutrons.【单选题】

A.Right

B.Wrong

C.Not mentioned

正确答案:B

答案解析:本题难度不大，答案依据比较明显，主要答案依据在文章第二段第二句：An atom of ordinary carbon，called carbon - 12，has six protons ａｎｄ　six neutrons谈到普通碳原子有6个质子和6个中子，显然，题干和答案依据不符，答案是B。

4、Cell Phones1. Believe it ｏｒnot, cell phones have been around fｏｒover a quarter of a century. The first commercial cell phone system was developed by the Japanese in 1979, but cell phones have changed a lot since that time. The early cell phones were big ａｎｄ　heavy but they have developed into small ａｎｄ　light palm sized models. There are huge developments in their functions, too. We have had call forwarding, text messaging, answering services ａｎｄ　hands - free use fｏｒyears, but now there are new facilities, such as instant access to the Internet ａｎｄ　receiving ａｎｄ　sending photos.2. Cell phones have become very common in our lives. Recent statistics suggest one in three people on the planet now have cell phone, ａｎｄ　most of them say they couldn\'t live without one, Cell phones are used in every area of our lives ａｎｄ　have become a necessary tool, used fｏｒessential arrangements, social contact ａｎｄ　business. It easier to call fｏｒhelp on the highway. It possible to keep in touch with people "on the move" when people are traveling.3. Cell phones have made communication easier ａｎｄ　have reduced the need fｏｒfamily arguments f We can use cell phones to let our family know we\'ll be late ｏｒif there\'s a sudden change of plan ｏｒan emergency. Cell phones have eased the worries of millions of parents when their teenagers are out late. They can now contact their children at any time.4. This does not mean that cell phones are all good news. Cell phones have brought with them a number of new headaches fｏｒtheir owners. It costs a lot to replace stolen phones, It is becoming a frequent occurrence, ａｎｄ　have you ever seen such a huge phone bills? More serious, however, Cell phones bring the potential health problem. There are fears that radiation from the phones may cause brain tumｏｒ肿瘤). This may be a time bomb waiting to happen to younger people who have grown up with cell phones. They simply can\'t live without cell phones!Cell phones are common in our lives ａｎｄ　have become ______.【单选题】

A.a necessity

B.an emergency

C.a number of new headaches

D.family arguments

E.big ａｎｄ　light palm - sized models

F.countless new facilities

正确答案:A

答案解析:本题难度不大，虽然答案依据不太明显，但第二段的主旨句可以看做是答案依据，通读第二段，可以判断出手机已成一个必需的工具，所以答案是A。

5、The test produced disappointing results.【单选题】

A.unsatisfactory

B.indirect

C.similar

D.positive

正确答案:A

答案解析:实验结果令人失望。本题难度不大，也是送分题，可以确认disappointing和unsatisfactory都是“失望的，让人不满意的”意思，所以最佳答案是A。