2019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、Black Holes
Most 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)
Black holes are part of space.
【单选题】

A.Right

B.Wrong

C.Not mentioned

正确答案:A

答案解析:题干大意：黑洞是太空的一部分。用space回到原文定位，文中首段第三句提到：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). 天文学家认为黑洞的中心是太空中的一个单一的无限密度的点。第二段第一句也有信息提到：This single point is called a singularity (奇点). 这个单一的点叫做奇点。故答案选A。

2、Arctic Melt
Earth's North and South Poles are famous for being cold and icy. Last year, however, the amount of ice in the Arctic Ocean fell to a record low.
Normally, ice builds in Arctic waters around the North Pole each winter and shrinks during the summer. But for many years, the amount of ice left by the end of summer has been declining.
Since 1979, each decade has seen an 11. 4 percent drop in end of summer ice cover. Between 1981 and 2000, ice in the Arctic lost 22 percent of its thickness, becoming 1.13 meters thinner.
Last summer, Arctic sea ice reached its skimpiest levels yet. By the end of summer 2007, the ice had shrunk to cover just 4.2 million square kilometers. That's 38 percent less area than the average cover at that time of year. And it's a very large 23 percent below the previous record low, which was set just 2 years ago. This continuing trend has scientists concerned.
There may be several reasons for the ice melt, says Jinlun Zhang, an oceanographer at the University of Washington at Seattle. Unusually strong winds blew through the Arctic last summer. The winds pushed much of the ice out of the central Arctic, leaving a large area of thin ice and open water.
Scientists also suspect that fewer clouds cover the Arctic now than in the past. Clearer skies allow more sunlight to reach the ocean. The extra heat warms both the water and the atmosphere. In parts of the Arctic Ocean last year, surface temperatures were 3.5℃ warmer than average and 1.5℃ warmer than the previous record high.
With both air and water getting warmer, the ice is melting from both above and below. In some parts of the Beaufort Sea, north of Alaska and western Canada, ice that measured 3. 3 meters thick at the beginning of the summer measured just 50 centimeters by season's end.
The new measurements suggest that melting is far more severe than scientists have seen by just looking at ice cover from above, says Donald K. Perovich, a geophysicist at the U. S. Army Cold Regions Research and Engineering Laboratory in Hanover, N. H.
Some scientists fear that the Arctic is stuck in a warming trend from which it may never recover.
What are the reasons for the ice melting according to the scientists?
【单选题】

A.strong winds and clear skies

B.long summer and short winter

C.open water and thin ice

D.light clouds and light winds

正确答案:A

答案解析:第5段最后一句和第6段第1句、第2句说明了科学家们推测的冰川融化原因：一为强风；二为较少的云，即clear skies。

3、Seeing Red Means Danger Ahead
The 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 switching material. It will turn red before a structure collapses or falls apart.
The secret behind the color switching material is a particular type of molecule. A molecule is a group of atoms held together by chemical bonds. Molecules come at all shapes and sizes, and make up ______. 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 switching molecule called a mechanophore (机械响应性聚合物) which is about to break, it produce a color. When a polymer with mechanophore molecules becomes "injured" or weak, one of the 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 switching polymers in their lab. The test results proved encouraging.
There is a way to get rid of the color light when a bright light is shone on the mechanophore.
The broken bond is fixed and the red color disappears. This "self-healing" may be a problem for engineers. They need to use the color changer in big construction projects that will be outside in sunlight. And sunlight will make the mechanophore's warming system useless. Sottos and her fellow scientists still have a lot of work to do before the color switching molecules can be used outside the lab.
【单选题】

A.nothing

B.anyone

C.someone

D.everything

正确答案:D

答案解析:本句的意思是分子本身形状不一，但构成了各种我们肉眼所看到的事物。make up:组成；you can see做前面宾语的补语。根据上下文文意，应选择everything。

4、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 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。

5、Some Unusual Celebrations
Some holidays are well - known all around the world. Among them are New Year's Eve celebrations. Also common are days in honor of love and friendship, like Valentine's Day. Each country has its own special holidays too, often to mark important events in its history. Schools, banks and government offices all close on days like these. Some of the days people celebrate, however, are less serious. A few of them are really very strange.
Of course, they are not strange to the people who celebrate them. Perhaps that is because the celebrations have long traditions. Consider April Fool's Day, for example. No one knows when or why it began. Today it is celebrated in many countries—France, England and Australia, among others. On this day, people play practical jokes. Jokes are supposed to be funny, but these jokes do not make everyone laugh. The ones who laugh are the ones playing the jokes. The people they fool often get angry. Does celebrating this day make sense to you?
Dyngus Day in Poland seems strange too. On this day, it is traditional for boys to pour water over the heads of girls. Here is the strangest part, they do it to girls they like.
Other unusual celebrations take place in a single city or town. A holiday called La Tomatina is celebrated in Bunol, Spain. Every year, in late August, big trucks carry more than 200,000 pounds of tomatoes into this little town. Then begins the world-s biggest food fight. For two hours, people in the streets throw tomatoes at each other. Everyone ends up red from head to toe.
August 10 marks the start of the Puck Fair, an Irish festival with a very unusual tradition. People from the town of Killorglin go up into the mountains and catch a wild goat. _____
There are also some celebrations that are really strange. In the United States, sometimes one person gets an idea for a new holiday and tries to get others to accept it. Whose idea was Public Sleeping Day? That one is on February 28. It may seem strange, but it sounds like more fun than the one on February 29. That is supposed to be Toothache Day.
Do you like the idea of inventing a new holiday? If you do, then you will want to mark March 26 on your calendar. That is Make Up Your Own Holiday Day.
【单选题】

A.They bring him back to town, put a crown on his head, and make him king for three days.

B.Some of the days people celebrate, however, are less serious.

C.That is supposed to be Toothache Day.

D.Then begins the world-s biggest food fight.

E.Some people have fun imagining new holidays.

F.Jokes are supposed to be funny, but these jokes do not make everyone laugh.

正确答案:A

答案解析:本题有一定难度，文章此处讨论的是爱尔兰一个奇怪的节日，山羊节，回来看选项，只有A符合上下文逻辑，是答案。