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.The half - life of C - 14 is about 25 ,000 years.【单选题】

A.Right

B.Wrong

C.Not mentioned

正确答案:C

答案解析:本题有较大难度，答案依据不明显，需要通读全文作出判断。通读全文后可以发现文章并未提及碳的半衰期是25，000年，所以本题是未提及的，答案是C。

2、The minimum age of Chinese citizens who are eligible to vote is eighteen. 【单选题】

A.encouraged

B.enforced

C.entitled

D.expected

正确答案:C

答案解析:encouraged:被鼓励的、受到鼓舞的；enforced:受强迫的、被迫的；entitled:授权的、有资格的，和句子中的eligible意思相同；expected：受到期待的、被期望的、所预期的。

3、Mary has blended the ingredients.【单选题】

A.mixed

B.made

C.cooked

D.eaten

正确答案:A

答案解析:题干大意：玛丽已经把调料混合了。画线词blend：混合。四个选项中，mix：混合，掺和。made：做，安排。cook：做饭。eat：吃。根据判断只有mix符合题意，故答案选A。

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 lungs. 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 ______ 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.bring about

B.contributed to

C.promote

D.prevent

正确答案:D

答案解析:空白处的上一句实际上起到了提示作用：“两个月的治疗方案可以防止大约20%的新病例”，后一句自然应是“也可能防止大约20%的结核病死亡”。其他3个选项词义均相反。

5、Will We Take Vacation in Spaces?When Mike Kelly first set out to build his own private space-ferry service, he figured his bread-and-butter business would be lofting (发射) satellites into high-Earth orbit. Now he thinks he may have figured wrong. "People were always asking me when they could go," says Kelly, who runs Kelly Space & Technology out of San Bemardino, California. "I realized that real market is in space tourism."According to preliminary market surveys, there are 10,000 would-be-space-tourists willing to spend $1 million each to visit the final frontier. Space Adventure in Arlington, Virginia, has taken more than 130 deposits for a two-hour, $98, 000 space tour tentatively and somewhat dubiously (可疑地) set to actor by 2005. Gene Meyers of the space Island Group says: "Space is the next exotic(风光奇特的) vacation spot. "This may all sound great, but there are a few hurdles (困难). Putting a simple satellite into orbit with no oxygen, life support or return trip necessary already costs an astronomical (天文数字) $ 22,OOO/kg. And that doesn\'t include the oust of insuring rich and possibly litigious passenger. John Pike of the Federation of American Scientists acerbically (尖刻地) suggests that the entire group of entrepreneurs trying to corner (垄断) the space-tourism market have between them "just enough money to blow up one rocket."The U. S. space agency has plenty of money but zero interest in mailing space less expensive for the little guys. So the little guys are racing to do what the government has failed to do: design a reusable launch system that is inexpensive, safe and reliable. Kelly Space\'s prototype looks like a plane that has sprouted rocket engines. Rotary Rocket in Redwood City, California, has a booster with rotors to make a helicopter-style return to Earth; Kistler Aero-space in Kirkland, Washington, is piecing together its versions from old Soviet engines, shuttle-style thermal protection tiles and an elaborate parachute system. The first passenger countdowns are still years away, but bureaucrats at the Federal Aviation Administration in Washington are already informally discussing flight regulations. After all, you can\'t be too prepared, for a trip to that galaxy far, far away. For those who are intent on joining the 100-mile high club, Hilton and Budget are plotting to build space hotels. Before the Russian spaceship Mir came down, some people were talking about using it as a low-rent space hotel to reduce the cost. If a space hotel is finally built in space, and if you are thinking of staying in it, you may want to check the Michelin ratings before booking yourself a suite. Space Adventure in Arlington has taken 130 deposits totaling $98,000 for a two-hour space tour. 【单选题】

A.Right

B.Wrong

C.Notmentioned

正确答案:B

答案解析:第2段第2句的意思是：每人交100万美元的定金，而不是总共98 000美元，从这句话中可以看出历时两个小时的太空旅行计划在2005年，该旅行是试验性的，并且在一定程度上令人质疑。因此题干的说法是错误的。