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、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.Nowadays many scientists depend on radiocarbon for dating age - old objects.【单选题】

A.Right

B.Wrong

C.Not mentioned

正确答案:A

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一段第一段：Now-adays scientists can answer many questions about the past through a technique called radiocarbon，or carbon - 14 dating，谈到现在科学家可以通过一种叫做放射性碳定年法来解读过去，题干是其近义解释，所以正确，答案是A。

2、Singing Alarms Could Save the BlindIf you cannot see, you may not be able to find your way out of a burning building and that could be fatal. A company in Leeds could change all that with directional sound alarms capable of guiding you to the exit. Sound Alert, a company ______ the University of Leeds, is installing the alarms in a residential home for blind people in Sommerset and a resource centre for the blind in Columbia. The alarms produce a wide range of frequencies that enable the brain to determine where the sound is coming from. Deborah Withington of Sound Alert says that the alarms use most of the frequencies that can be heard by humans. "It\'s a burst of white noise that people say sounds like static on the radio," she says. "Its life-saving potential is great."She conducted an experiment in which people were filmed by thermal-imaging cameras trying to find their way out of a large smoke-filled room. It took them nearly four minutes to find the door without a sound alarm, but only 15 seconds with one. Withington studies how the brain processes sounds at the university. She says that the source of a wide band of frequencies can be pinpointed more easily than the source of a narrow band. Alarms basedon the same concept have already been installed on emergency vehicles. The alarms will also include rising or falling frequencies to indicate whether people should go up or down stairs. They were developed with the aid of a large grant from British Nuclear Fuels. 【单选题】

A.run by

B.changed by

C.decorated by

D.criticized by

正确答案:A

答案解析:我们知道Sound Alert是一家公司的名字，从语意上判断应该是由某人经营，因此选择A较为合适。

3、In the process, the light energy converts to heat energy.【单选题】

A.reduces

B.changes

C.leaves

D.drops

正确答案:B

答案解析:在这个过程中，光能转化成热能。本题难度不大，converts指“转变”，通常与to或者into搭配，和changes“变化”是近义词，其他三项都是常用词，和答案意义差异较大，干扰性不强。

4、Breastfeeding Can Cut Cardiovascular RiskBreastfeeding 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 now shown that breastfeeding and slow growth in the first weeks and months of life has a protective effect against cardiovascular disease. "Diets that promote more rapid growth put babies at risk many years later in terms of raising their blood pressure, raising their cholesterol and increasing their tendency to diabetes and obesity-the four main risk factors for stroke and heart attack." said Professor Alan Lucas of the Institute of Child Health in London. "Our evidence suggests that the reason why breast-fed babies do better is because they grow more slowly in the early weeks."Lucas said the effects of breastfeeding on blood pressure and cholesterol later in life are greater than anything adults can do to control the risk factors for cardiovascular disease, other than taking drugs. An estimated 17 million people die of cardiovascular disease, particularly heart attack and strokes, each year, according to the World Health Organization. Lucas and his colleagues compared the health of 216 teenagers who as babies had either been breastfed or given different nutritional baby formulas\' They reported their findings in The Lancet medical journal. The teenagers who had been breastfed had a 14 percent lower ratio of bad to good cholesterol and lower concentrations of a protein that is a marker for cardiovascular disease risk. The researchers also found that ______ of the child\'s weight at birth, the faster the infants grew in the early weeks and months of life, the greater was their later risk of heart disease and stroke. The effect was the same for both boys and girls. "The more human milk you have in the newborn period, the lower your cholesterol level is, the lower your blood pressure is 16 years later, "Lucas said. 【单选题】

A.despite

B.waming

C.regardless

D.needful

正确答案:C

答案解析:空白后出现了介词of，因此首先排除A（despite是介词）；剩下的选项中能与介词of搭配使用的是B和C：warning of…：对……的警告；regardless of…：不管……，不顾……。根据空白所在的搭配结构“. . . of the child\'s weight at birth（…孩子出生时的体重）”判断C放入空白处上下文意思通顺：不管孩子出生时的体重是多少。

5、Don\'t Rely on Plankton to Save the PlanetEncouraging plankton growth in the ocean has been touted by some as a promising way to remove carbon dioxide from the atmosphere. Its opponents fear that will damage the marine ecosystem, and now a computer model shows that the trick would also be remarkably inefficient.Adding iron to patched of ocean can make plankton bloom temporarily. The microscopic organisms suck up dissolved carbon dioxide from the water, which in turn is replaced by carbon dioxide from the air. As plankton die and settle on the ocean floor, their carbon is supposedly locked up in the seabed.Jorge Sarmiento from Princeton and his colleagues developed a complex computer model to analyze how factors such as ocean chemistry and water circulation would affect the process if 160,000 square kilometers of ocean were seeded with iron for a month. They found that 100 years later only between 2 and 13 percent of the extra carbon that was originally taken up plankton had actually been removed from the atmosphere.In their scenario, which covers an area 10 times as big as the largest experiment of this kind ever proposed, fertilizing the ocean removes 1 million tons of carbon from the atmosphere just 0.2 percent of the carbon dioxide humankind spews out each month. Rough estimates in the past have predicted similarly disappointing results."These are newer and better models," says Sallie Chisholm, an environmental engineer from the Massachusetts Institute of Technology."Butthe take-home message is the same.______."【单选题】

A.Its opponents argue, however, that it will stop global warming.

B.Its opponents fear that will damage the marine ecosystem, and now a computer model shows that the trick would also be remarkably inefficient.

C.As plankton die and settle on the ocean floor, their carbon is supposedly locked up in the seabed.

D.They found that 100 years later only between 2 and 15 percent of the extra carbon that was originally taken up plankton had actually been removed from the atmosphere.

E."These are newer and better models,"

F.Ocean fertilization is not the answer to global warming.

正确答案:F

答案解析:空白位置暗示该句句意的特点，往往是总结、概括句。对比剩下的选项A和F，选择F.考点：句子之间的逻辑发展。A根据all的习惯搭配：all＋指示代词，因此首先排除B（人称代词）。结合前句内容，空白处的代词应该指代前句中提到的“敏锐的眼睛和耳朵、反应迅速的大脑、手和大脑之间的协调”，因此应该选择指代复数的指示代词these。