2021年职称英语考试《综合类》考试共65题，分为单选题。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、A Strong Greenhouse Gas1 Methane is a colorless, odorless gas; it is also a potent greenhouse gas, and once released into the atmospheres, it absorbs beat radiating from Earth\'s surface. That\'s why methane is a major contributor to the planet\'s increasing temperature rise or global warming. Molecule for molecule, methane\'s heat-trapping power in the atmosphere is 21 times stronger than carbon dioxide, the most abundant greenhouse gas.2 With 13 billion cows belching almost constantly around the world (100 million in the U. S. alone), it\'s no surprise that menace released by livestock is one of the chief sources of the gas. Other prime methane sources: petroleum, drilling, coal mining, solid-waste landfills and wetlands.3 Greenhouse gases like methane and carbon dioxide make up only a small part of Earth\'s atmosphere, which is 78 percent nitrogen and nearly 21 percent oxygen. And without greenhouse gases to trap the sun\'s heat and warm the planet, life as we know it couldn\'t exist. But in the last200 years, human activity that requires burning oil, natural gas, and coal for energy has magnified the greenhouse effect.4 Atmospheric concentrations of methane have more than doubled in the last two centuries. Blame for this often focuses on big industries and gas-guzzling vehicles. But agriculture plays a major role, too. In the past 40 years alone, the global cattle population has doubled.5 Cows munch mostly grasses and hay yet they grow big and hefty. Why? Because of the rumen. The rumen holds 160 liters of food and billions of microbes. These microscopic bacteria and protozoa break down cellulose and Fiber into digestible nutrients. A cow couldn\'t live without its microbes. As the microbes digest cellulose, trey release methane. The process occurs in all animals with a rumen (cows, sheep, and goats, for example), and it makes them very gassy. It\'s part of their normal digestion process. When they drew their cud, they regurgitate some food to rechew it, and all this gas comes out. The average cow expels 600 liters of methane a day.That\'s why we say livestock gas is also a major factor of causing the global warming.Paragraph 2 ____【单选题】

A.Life of Macroscopic Bacteria in Livestock\'s Rumen

B.Ways to Reduce Methane\'s Heat-trapping Power

C.Agriculture Also Contributes to Increased Concentrations of Methane in the Atmosphere

D.Why Livestock Releases Methane

E.Methane as a Strong Greenhouse Gas

F.Livestock as a Prime Factor of the Greenhouse Effect

正确答案:F

答案解析:本段要表达的中心意思是：livestock排出的甲烷也是温室效应的一个主要源头。

2、A Carrot a Day Keeps Cancer AwayAmong all the malignancies, lung cancer is the biggest killer: more than 100,000 Americans a year die of the disease. Giving up smoking is one of obvious way to reduce the risk, but another answer may lie in the kitchen. According to a new report, even heavy smokers may be protected from developing lung cancer by a simple dietary measure: a daily portion of carrots, spinach or any other vegetable or fruit containing a form of vitamin A called carotene.The finding, published in the British medical journal The Lancet, is part of a long-range investigation of diet and disease. Since 1957 a team of American researchers has monitored the dietary habits and medical histories of 2,000 middle-aged men employed by the Western Electric Co. in Chicago. Led by Dr. Richard Shelelle of Chicago\'s Rush-Presbyterian, St. Luke\'s Medical Center, the researchers recently began to sort out the links between the subjects\' dietary patterns and cancer. Other studies of animals and humans have suggested that vitamin A offers some protection against lung cancer. The correlation seemed logical, since vitamin A is essential for the growth of the epithelial (上皮的) tissue that lines the airways of the lungs.Vegetables: But the earlier research did not distinguish between two different forms of the vitamin. "Preformed" vitamin A, known as retinol, is found mainly in liver and dairy products like milk, cheese, butter and eggs. But vitamin A is also made in the body from carotene, which is abundant in a variety of vegetables and fruits, including carrots, spinach, squash, tomatoes, sweet potatoes and apples.In the Western Electric study, Shekelle and his colleagues found little correlation between the incidence of lung cancer and the consumption of foods containing preformed vitamin A, but when they examined the data on carotene intake, they discovered a significant relationship. Among the488 men who had the lowest level of carotene consumption, there were fourteen cases of lung cancer, in a group of the same size that ate the most carotene, only two cases developed. The apparent protective effect of carotene held up even for longtime smokers but to a lesser degree.Further studies will be necessary before the link between lung cancer and carotene can be firmly established. In the meantime, researchers warn against taking large numbers of vitamin A pills, because the tablets contain a form of the chemical that can be extremely toxic in high doses. Instead, they advise a well-balance diet that includes foods rich in carotene. For a smoker, a half-cup of carrots every day might possibly make the difference between life and death.Among the groups studied, who had the most cases of lung cancer?【单选题】

A.Those with the lowest level of carotene intake.

B.Those with the highest level o carotene intake.

C.Those who ate only foods containing carotene.

D.Those with the lowest intake of carrots.

正确答案:A

答案解析:根据第4段，“在摄入胡萝}、素最少的488人中，有14例肺癌患者。而人数同样多的另一组摄入胡萝卜素最多的人群中只有2例”，因此答案是A。

3、Gun Rights in the USImmediately after the shooting at Virginia Tech University, Americans gathered to mourn (致哀) the dead. The president and the state governer both hurried there to share the grief. But the majority of Americans still cling to their right to own weapons.Strictly speaking, the US is not the only country here gun violence has destroyed lives, families and communities in everyday circumstance. But the US is one of the few countries that seem unwilling and politically incapable of doing anything serious to stop it.In countries like Britain and Canada, the government adopted strict gun control soon after serious gun violence incidents. US leaders, however, are held hostage by the gun lobby (院外活动集团) and the electoral (选举) system.The powerful National Rifle Association, the major supporter of gun rights in the US, is too strong for any party to take on. Most Republicans oppose gun control anyway. Over the years, the Democrats have found that they can either campaign for gun control or win power, not both, they prefer power.According to the US Bureau of Justice Statistics, firearm (火器) incidents accounted for nine percent of the 4.7 million violent crimes in 2005. So although opinion polls show most Americans want stricter gun laws, many people don\'t want to give up their arms they keep to protect themselves.Dave Hancock, a Virginia gun lover, is one example. In an interview he said, "If one professor in the Virginia incident had been carrying a legal weapon, they might have been able to stop all this. "In his opinion, the massacre (大屠杀) is an argument for more people to carry weapons, not fewer.Americans\' clinging to the right to bear arms is not just a fear of crime, but a mistrust of government, commented UK\'s Guardian newspaper.One Virginia resident, who had a permit to carry a concealed (隐藏的) firearm, told the Guardian that it was every American\'s responsibility to have a gun."Each person," he said, "should not rely solely ____ the government for protection."【单选题】

A.in

B.on

C.at

D.from

正确答案:B

答案解析:本题难度不大，考查的是动词短语rely on，rely on是“依靠”的意思，接介词on或upon，最佳答案是B。

4、The high - speed trains can have a major impact on our lives.【单选题】

A.effort

B.problem

C.influence

D.concern

正确答案:C

答案解析:高铁会对我们的生活产生很大影响。本题难度不大，是送分题，干扰项可以说无干扰性，确定impact的引申意义有“影响”的意思，不难找到答案influence。

5、What are my chances of promotion if I stay here?【单选题】

A.retirement

B.advertisement

C.advancement

D.replacement

正确答案:C

答案解析:如果我还待在这干，我有升职的机会吗？promotion指“提升，晋级”，和advancement的引申意义“晋升”是同义词，A项指“退休”，B项指“广告”，D项指“代替”，三项的干扰性不强。本题考查的是advancement的引申意义。