职称英语考试《理工类》章节练习题精选及答案0516-90

职称英语考试《理工类》章节练习题精选及答案0516-371、Seeing Red Means Danger AheadThe color red often means danger and by paying attention, accidents can be prevented. In the future, the color red also may help prevent danger at construction sites. Thanks to new work by engineers, bridge supports or other kinds of materials, could one day contain a color -changing material. It will turn red before a structure collapses or falls apart.The secret behind the color - changing material is a particular type of molecule (分子). A molecule is a group of atoms (原子) held together by chemical bonds. Molecules come in all shapes and sizes and make up everything you can see, touch or feel. How a molecule behaves depends on what kinds of atoms it contains and how they're held together.When a polymer (聚合物) containing a color -changing molecule called a mechanophore (机械响应性聚合物) is about to break, it produces a color. When a polymer with mechanophore molecules becomes "injured" or _____, one ofthe mechanophore bonds breaks and the material turns red. "It's a really simple detection method," says Nancy Sottos, one of the scientists who worked on the project. Sottos and her team tested the color - changing polymers in their lab. The test results proved encouraging.There is a way to get rid of the red color light. When a bright light is shone on the mechanophore, the broken bond is fixed and the red color disappears. Thus "self -healing" may be a problem for engineers. They need to use the color - changer in big construction projects that will be outside, under sunlight. And sunlight will make the mechanophore's warning system useless.Sottos and her fellow scientists still have a lot of work to do before the color - changing molecules can be used outside the lab.【单选题】A.strongB.softC.weakD.hard正确答案:C答案解析:本题有一定难度，关键在理解好文章上下文意义，文章此处的or表明后面用词要和injured相近，答案是C。

职称英语考试《理工类》章节练习题精选及答案0516-681、Lakes, Too, Feel Global WarmingThere's no doubt, In the last few decades, the average temperature on Earth has been higher than it has been in hundreds of years. Around the world, people are starting to measure the effects of global warming and trying to figure out what to do about it.Scientist recently used satellites to study the temperatures of lakes around the world and they found that lakes are heating up. Between 1985 and 2009, satellites recorded the night time temperatures of the surfaces of 167 lakes. During those 24 years, the lakes got warmer by an average of about 0.045 degree Celsius per year.In some places, lakes have been warming by as much as 0.10 degree Celsius per year. At that rate, a lake may warm by a full degree Celsius in just 10 years. That difference may seem small you might not even notice it in your bath. But in a lake, slightly warmer temperatures could mean more algae (水藻) and algae can make the lake poisonous to fish.The study shows that in some regions, lakes are warming faster than the air around them. This is important because scientists often use measurements of air temperature to study how Earth is warming. By using lake temperatures as well, scientists can get a better picture of global warming. The scientists say data on lakes give scientists a new way to measure the impact of climate change around the world.That's going to be useful, since no matter the country is too big or too small can't ignore climate changes. Scientists aren't the only ones concerned. Everyone who lives on Earth is going to be affected by the rapid warming of the planet. Many world leaders believe we might be able to do something about it, especially by reducing the amount of greenhouse(温室) gases we put into the air.That's why the United Nations started the Framework Convention on Climate Change, or UNFCCC. Every year the convention meets, and representatives from countries around the world gather to talk about climate change and discuss global solutions to the challenges of a warming world. UNFCCC's annual meeting will be held in Mexico this year.【单选题】A.RightB.WrongC.Not mentioned正确答案:C答案解析:本题难度较大，答案依据不明显，需要通读全文。

职称英语考试《理工类》章节练习题精选及答案0516-361、A Bad IdeaThink you can walk, drive, take phone calls, e - mail and listen to music at the same time 7 Well, New York's new law says you can't. And you'll be fined $ 100 if you do so on a New York city street. The law went into force last month, following research and a shocking number of accidents that involved people using electronic gadgets (小巧机械) when crossing the street.Who's to blame? _____. "We are under the impression that our brain can do more than it often can," says Rene Marois, a neuroscientist (神经科学家) in Tennessee. "But a core limitation is the inability to concentrate on two things at once." The young people are often considered the great multitaskers. However, an Oxford University research suggests this perception is open to question. A group of 18 to 21 years old and a group of 35 to 39 years old were given 90 seconds to translate images into numbers, using a simple code. The younger group did 10 percent better when not interrupted. But when both groups were interrupted by a phone call or aninstant message, the older group matched the younger group in speed and accuracy.It is difficult to measure the productivity lost by multitaskers. Jonathan Spira, chief analyst at Basex, a business - research firm, estimates that the cost of interruptions to the American economy is nearly $ 650 billion a year. The estimate is based on surveys with office workers. The surveys conclude that 28 percent of the workers' time was spent on interruptions and recovery time before they returned to their main tasks.【单选题】A.Talking on a cell phone while driving brings you joy anyway.B.The estimate is based on surveys with office workers.C.The younger group did 10 percent better when not interrupted.D.However, an Oxford University research suggests this perception is open to question.E.Scientists say that our multitasking (多任务处理) abilities are limited.F.And you'll be fined $ 100 if you do so on a New York city street.正确答案:E答案解析:本题难度很大。

职称英语考试《理工类》章节练习题精选及答案0516-781、Black HolesMost scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe is not a solid object, like a planet, but it is shaped like a sphere (球体). Astronomers (天文学家) think that at the center of a black hole there is a single point in space with infinite (无限的) density (稠密).This single point is called a singularity (奇点). If the singularity theory is correct, it means that when a massive star collapses, all the material in it disappears into the singularity. The center of a black hole would not really be a hole at all, but an infinitely dense point. Anything that crosses the black hole is pulled in by its great gravity.Although black holes do exist, they are difficult to observe. These are the reasons,?No light or anything else comes out of black holes. As a result,they are invisible to a telescope.?In astronomical terms, black holes are truly. For example, a black hole formed by the collapse of a giant star would have an event horizon (视界) only 18 miles across.?The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion (万亿) miles. Even the most powerful telescopes could not pick out an object so small at such a great distance.In 1994 the Hubble Space Telescope provided evidence that black holes exist. There are still answers to be found, however, so black holes remain one of the mysteries of the universe. (2007年)The sun is the heaviest star in the universe.【单选题】A.RightB.WrongC.Not mentioned正确答案:C答案解析:题干大意：在宇宙中，太阳是最重的星体。