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、The Threat to KiribatiThe people of Kiribati are afraid that one day in the not-too-distant future, their country will disappear from the face of the earth-literally. Several times this year, the Pacific island nation has been flooded by a sudden high tide. These tides, which swept across the island and destroyed houses, came when there was neither wind nor rain. "This never happened before," say the older citizens of Kiribati.What is causing these mysterious high tides? The answer may well be global warming. When fuels like oil and coal are being burned, pollutants (污染物) are released. These pollutants trap heat in the earth\'s atmosphere. Warmer temperatures cause water to expand and also create more water by melting glaciers (冰川) and polar (极地的) ice caps.If the trend continues, scientists say, many countries will suffer, Bangladesh, for example, might lose one-fifth of its land. The coral (珊瑚) island nations of the Pacific, like Kiribati and the Marshall Islands, however, would face an even worse fate-they would be swallowed by the sea. The loss of these coral islands would be everyone\'s loss. Coral formations are home to more species than any other place on earth.The people of these nations feel frustrated. The sea, on which their economies have always been based, is suddenly threatening their existence. They don\'t have the money for expensive technological solutions like seawalls. And they have no control over the pollutants, which are being released mainly by activities in large industrialized countries. All they can do is to hope that industrialized countries will take steps to reduce pollution.The heat released by burning oil and coal is the direct cause of global warming.【单选题】

A.Right

B.Wrong

C.Not mentioned

正确答案:B

答案解析:题干大意：燃烧石油和煤放出的热量是全球变暖的直接原因。文章第二段提到：When fuels like oil and coal are being burned, pollutants (污染物) are released. These pollutants trap heat in the earth\'s atmosphere. 当燃料（如石油和煤）被燃烧，释放污染物，这些污染物圈住地球大气层中的热量。这是引起全球变暖的一个原因。而题干把它范围缩小，说成直接原因，故答案选B。

3、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 ______ 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 regardless 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.slowly

B.quickly

C.strongly

D.obviously

正确答案:A

答案解析:A和B是正反项，重点注意。根据句意和前句中提到的内容——婴儿的头几周和头几个月发育缓慢，对预防心血管疾病有帮助，由此判断A是答案。

4、Better Control of TB Seen if a Faster Cure is FoundThe World Health Organization estimates that about one-third of all people are infected with bacteria that cause tuberculosis. Most times, the infection remains inactive. But each year about eight million people develop active cases of TB, usually in their ______. Two million people die of it. The disease has increased with the spread of AIDS and drug-resistant forms of tuberculosis. Current treatments take at least six months. Patients have to take a combination of several antibiotic drugs daily. But many people stop as soon as they feel better. Doing that can lead to an infection that resists treatment. Public health experts agree that a faster-acting cure for tuberculosis would be more effective. Now a study estimates just how effective it might be. A professor of international health at Harvard University led the study. Joshua Salomon says a shorter treatment program would likely mean not just more patients cured. It would also mean fewer infectious patients who can pass on their infection to others. The researchers developed a mathematical model to examine the effects of a two-month treatment plan. They tested the model with current TB conditions in Southeast Asia. The scientists found that a two-month treatment could prevent about twenty percent of new cases. And it might prevent about twenty-five percent of TB deaths. The model shows that these reductions would take place between two thousand twelve and two thousand thirty. That is, if a faster cure is developed and in wide use by two thousand twelve. The World Health Organization developed the DOTS program in nineteen ninety. DOTS is Directly Observed Treatment, Short-course. Health workers watch tuberculosis patients take their daily pills to make sure they continue treatment. Earlier this year, an international partnership of organizations announced a plan to expand the DOTS program. The ten-year plan also aims to finance research into new TB drugs. The four most common drugs used now are more than forty years old. The Global Alliance for TB Drug Development says its long-term goal is a treatment that could work in as few as ten doses.【单选题】

A.kidneys

B.lungs

C.bones

D.livers

正确答案:B

答案解析:结核病多发于肺部，这是一般的常识。

5、Sharing SilenceDeaf teenagers Orlando Chavez and German Resendiz have been friends since kindergarten (幼儿园). Together the two boys, who go to Escondido High School in California, have had the difficult job of learning in schools where the majority of the students can speak and hear.Orlando lost his hearing at the age of one. German was born deaf, and his parents moved from Mexico to find a school where he could learn sign language. He met Orlando on their first day of kinder garten."We were in a special class with about 25 other deaf kids," German remembered. "Before then, I didn\'t know I was deaf and I was different.""Being young and deaf in regular classes was very hard," signs Orlando. "The other kids didn\'t understand us and we didn\'t understand them. But we\'ve all grown up together, and today, I\'m popular because I\'m deaf. Kids try to communicate with me."Some things are very difficult for the two boys. "We can\'t talk on the phone, so if we need help, we can\'t call an emergency service," German signs. "And we can\'t order food in a drive - thru."Despite of their difficulties, the two boys have found work putting food in bags at a local supermarket.They got their jobs through a "workability" program, designed for teenagers from local schools with different types of learning disabilities.German has worked in the supermarket since August, and Orlando started in November."The other people who work here nave been very nice to us," Orlando signs. "They even sign sometimes. At first, we were nervous, but we\'ve learned a lot and we\'re getting better."The opportunity to earn money has been exciting, both boys said. After high school, they hope to attend the National Technical Institute for the Deaf in New York.The word "emergency" in paragraph 5 is closest in meaning to ______.【单选题】

A.food

B.alarm

C.crisis

D.quick

正确答案:C

答案解析:本题难度不大，干扰项干扰不强，考生会很快确定答案。emergency指“紧急”，和crisis“危机，紧急关头”是近义词。B项alarm指“警戒”，最佳答案是C。