| 职称英语考试理工类每日一练（2015-12-1） |
| 第1、2、3、4、5、6、7题： Radiocarbon Dating Nowadays 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 by something happened is to discover when it happened. Radiocarbon dating was developed in the late 1940s by physicist Willard F. Libby at he University of Chicago. An atom of ordinary carbon, called carbon-12, has six protons(中子) and six neutrons (质子) in its nucleus. Carbon-14, or C-14, is a radioactive, unstable form of carbon that has two extra neutrons (原子核). It returns to a more stable form of carbon through a process called decay (衰减). This process involves the loss of he extra neutrons and energy from the nucleus. In Libby's radiocarbon dating technique, the weak radioactive emissions (放射) from his decay process are counted by instruments such as a radiation detector and counter. he 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 mount 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 toms 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 tops 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 toms goes down. In terms of radiocarbon dating, the fewer C-14 atoms in a sample, the older that sample is. 16 Nowadays many scientists depend on radiocarbon for dating age-old objects A Right B Wrong C Not mentioned 17 The radiocarbon dating technique is only about 40 years old A Right B Wrong C Not mentioned 18 An atom of ordinary carbon has six protons and eight neutrons A Right B Wrong C Not mentioned 19 Radar is used to determine the characteristics of radiocarbon A Right B Wrong C Not mentioned 20 Radiocarbon is reliable in dating an object back to at least 50,000 years. A Right B Wrong C Not mentioned 21 The C-14 in an organism begins to decay when it dies A Right B Wrong C Not mentioned 22 The half-life of C-14 is about 25,000 years. A Right B Wrong C Not mentioned |
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| 第8题： He asserted that nuclear power was a safe and non-polluting energy source. A maintained B recommended C considered D acknowledged |
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| 第9、10、11、12、13、14、15题： British Women's Waistlines The average British woman's waistline has grownby 2 inches in 10 years, all thanks to the sedentary（久坐的） lifestyle. A study conducted by Cancer Research UKscientists found that the average waistline of British women has increased from31.8 inches to 33.5 inches. Men are also nowhere behind the fairer sex, forthe research found that the average man's waistline has grown by 1.4 inches to38 inches. "We know high body weight increases therisk of a number of cancers and it is important we get this message out to asmany people as possible,” the Daily Mail quoted DrLesley Walker, of Cancer Research UK, as saying. "A healthy diet with plenty of fiber,fruit and vegetables, as well as regular exercise can help people lose weightand reduce their risk of cancer,” he added. The trend was found to be dominant in the under45s, where the proportion of men with a body mass index（体重指数）over 35, and of women with a BMI of over 40, has grown two-foldduring the decade. Lead researcher Professor Jane Wardle said itis possible that young people follow a less healthy lifestyle than theirelders. "Snacking habits, takeaway meals high infat and sedentary lifestyles where many people spend both work and leisure timesitting in front of a computer are all likely to contribute to theresults." She added that genetics also play a vital rolein the growing rate of obesity. 1、British women’s waistline would have grown more than 2 inches if they didn’t spend too much time sitting A.Right B.Wrong C.Not mentioned 2、The exact increase ofthe average waistline of British women is 1.7 inches A.Right B.Wrong C.Not mentioned 3、Men’s waistline has grown because they have eaten too many hamburgers A.Right B.Wrong C.Not mentioned 4、Dr Walker believesthe heavier the body is, the higher risk there is of cancers A.Right B.Wrong C.Not mentioned 5、People over 45 aremost likely to have high body weight A.Right B.Wrong C.Not mentioned 6、Young people follow ahealthier lifestyle than their parents A.Right B.Wrong C.Not mentioned 7、Wardle believesgenetics have nothing to do with obesity A.Right B.Wrong C.Not mentioned |
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| 第16题：I wonder what your aim in life is. A.symbol B.goal C.action D.attitude |
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| 第17题：Mary looked pale and weary. A.worried B.ugly C.silly D.exhausted |
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| 第18题：I want to provide my boys with a decent education. A.good B.special C.private D.general |
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| 第19、20、21、22、23题： Citizen Scientists Understanding how nature responds to climate change will require monitoring key life cycleevent-flowering，the appearance of leaves，the first frog calls of the spring all around the world． But ecologists can't be everywhere so they're turning to non-scientists，sometimes called citizen scientists，for help． CIimate scientists are not present everywhere．Because there are so many places in the worldand not enough scientists to observe all of them，they're asking for your help in observing signs ofclimate change across the world．The citizen scientist movement encourages ordinary people too bserve a very specific research interest-birds，trees，flowers budding，etc．and send their observationsto a giant database to be observed by professional scientists．This helps a small number of scientiststrack a large amount of data that they would never be able to gather on their own．Much like citizenjournalists helping large publications cover a hyper-local beat，citizen scientists are ready for theconditions where thev live． All that's needed to become one is a few minutes each day or each weekto gather data and send it in． A group of scientists and educators launched an organization last year called the National Phenology Network．"Phenology"is what scientists call the study of the timing of events in nature. One of the group's first efforts relies on scientists and non-scientists alike to collect data about plant flowering and leafing every year．The program，called Projeet BudBurst，collects life cycle da. ta on a variety of common plants from across the United States．People participating in the projectwhich is open to everyone record their observations on the Project BudBurst website． "People don't have to be plant experts，they just have to look around and see what's in their neighborhood，"says Jennifer Schwartz，an education consultant with the project．"As we collectthis data．we'll be able to make an estimate of how plants and communities of plants and animals will respond as the climate changes．" 36．Ecologists turn to non-scientist citizens for help because they need them__________________． A．to provide their personal life cycles B．to observe the life cycle of plants C．to collect data of the life cycle of living things D．to teach children knowledge about climate change 37．What are citizen scientists asked to do? A．To develop a specific research interest and become professional scientists． B．To send their research observations to a professional database． C．To increase their knowledge about climate change． D．To keep a record of their research observations． 38．In"All that，s needed to become one…(paragraph2)"，what does the word"one"stands for? A．a citizen journalist B．a citizen scientist C．a scientist D．a citizen 39．What is NOT true of Project BudBurst? A．Only experts can participate in it． B．Everybody can participate in it． C．It collects life cycle data on a variety of common plants． D．It has its own website． 40．What is the final purpose of Project BudBurst? A．To study when plants will have their first buds． B．To find out the types of plants in the neighborhood． C．To collect life cycle data on a variety of common plants from across the United States． D．To investigate how plants and animals will respond as the climate changes |
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| 第24、25、26、27、28、29、30、31、32、33、34、35、36、37、38题： Sharks Perform a Service for Earth's Waters It is hard to get people to think of sharks as anything but a deadly enemy. They are thought to （51） people frequently. Although these fish perform a valuable （52） for earth's waters and for human beings， business and sport fishing are threatening their （53） 。 As a result， some sharks are at risk of disappearing from Earth. Warm weather may influence both fish and shark （54） 。 Many fish swim near coastal areas because of their （55） waters. Experts say sharks may follow the fish into the same areas， （56） people also swim. In fact， most sharks do not purposely charge at or bite humans. They are thought to mistake a person （57） a sea animal， such as a seal （海豹） or sea lion. That is why people should not swim in the ocean when the sun goes down or comes up， because those are the times when sharks are looking for （58） 。 Experts also say that bright colors and shiny jewelry （珠宝） may cause sharks to attack. A shark has an extremely 'good sense of （59） ， with which it can find small amounts of substances in water， such as blood， body liquids and chemicals （60） by animals. These powerful senses help sharks find their food. Sharks eat fish， any （61） sharks， and plants that live in the ocean. Medical researchers want to learn more about the shark's body defense and immune （免疫的） （62） against disease. Researchers know that sharks （63） quickly from injuries. They study the shark in hopes of finding a way to fight human disease. Sharks are important for the world's oceans， as they eat injured and diseased fish. Their （64） activities mean that the numbers of other fish in ocean waters do not become too （65） 。 This protects the plants and other forms of life that exist in the oceans. 51 A attack B meet C recognize D visit 52 A research B experiment C service D analysis 53 A power B existence C mates D skills 54 A intelligence B shape C size D activity 55 A fresh B soft C warm D deep 56 A whose B which C that D where 57 A to B for C as D with 58 A food B help C friends D trainers 59 A humor B security C smell D touch 60 A contained B produced C used D added 61 A those B these C another D other 62 A systems B processes C ideas D theories 63 A recover B escape C return D cut 64 A mental B hunting C social D swimming 65 A weak B little C few D great |
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| 第39题： Many forms of cancer can be cured if detected early A.selected B.operated C.discovered D.developed |
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| 第40题：His stomach felt hollow with fear . A.sincere B.respectful C.empty D.terrible |
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