题目内容
（请给出正确答案）
A、actual crystallizing temperature is always below theoretic crystallizing temperature
B、actual crystallizing temperature is always equal to theoretic crystallizing temperature.
C、actual crystallizing temperature is always higher than theoretic crystallizing temperature
D、actual crystallizing temperature and theoretic crystallizing temperature have no relationship.
如搜索结果不匹配，请 联系老师 获取答案
更多“In practical production, when …”相关的问题
第1题
A、actual crystallizing temperature（实际结晶温度） is always below theoretic crystallizing temperature（理论结晶温度）.
B、actual crystallizing temperature is always equal to theoretic crystallizing temperature.
C、actual crystallizing temperature is always higher than theoretic crystallizing temperature.
D、actual crystallizing temperature and theoretic crystallizing temperature have no relationship.
第2题
A.a current will flow
B.a power will develop
C.a heat will flow
D.a pressure will produce
第3题
Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A, B, C and D. You should decide on the best choice.
As the horizons of science have expanded, two main groups of scientists have emerged. One is the pure scientist; the other, the applied scientist.
The pure or theoretical scientist does original research in order to understand the basic laws of nature that govern our world. The applied scientist adapts this knowledge to practical problems. Neither is more important than the other, however, for the two groups are very much related.
Sometimes the applied scientist finds the "problems" for the theoretical scientist to work on. Let's take a particular problem of the aircraft industry: heat-resistant metals. Many of the metals and alloys(合金) that perform. satisfactorily in a car cannot be used in a jet-propelled plane. New alloys must be used, because the jet engine operates at a much higher temperature than an automobile engine. The turbine wheel in a turbo-jet must withstand temperatures as high as 1,600 degrees Fahrenheit, so aircraft designers had to turn to the research metallurgist(冶金学者) for the development of metals and alloys that would do the job in jet-propelled planes.
Dividing scientists into two groups—pure and applied—is only one broad way of classifying them, however, when scientific knowledge was very limited, there was no need for men to specialize. Today, with the great body of scientific knowledge, scientists specialize in many different fields. Within each field, there is even further division. And, with finer and finer divisions, the various sciences have become more and more interrelated until no one branch is entirely independent of the others. Many new specialties—geophysics and biochemistry, for example—have resulted from combining the knowledge of two or more sciences.
The statement "the horizons of science have expanded"(Line 1, Para. 1) means that______.
A．the horizon is enlarged by scientists
B．scientists can observe further space
C．scientist9 are making efforts to expand the outer space
D．science has developed more fields
第4题
The pure or theoretical scientist does original research in order to understand the basic laws of nature that govern our world. The applied scientist adapts this knowledge to practical problems. Neither is more important than the other, however, for the two groups are very much related. Some times, however, the applied scientist finds the "problem" for the theoretical scientist to work on. Let' s take a particular problem of the aircraft industry: heat-resistant metals. Many of the metals and alloys which perform. satisfactorily in a car cannot be used in a jet-propelled plane. New alloys must be used, because the jet engine operates at a much higher temperature than an automobile engine. The turbine wheel in a turbojet must withstand temperatures as high as 1,600 degrees Fahrenheit, so aircraft designers had to turn to the research metallurgist for the development of metals and alloys that would do the job in jet-propelled planes.
Dividing scientists into two groups is only one broad way of classifying them, however. When scientific knowledge was very limited, there was no need for men to specialize. Today, with the great body of scientific knowledge, scientists specialize in many different fields. Within each field, there is even further subdivision. And, with finer and finer subdivisions, the various sciences have become more and more interrelated until no one branch is entirely independent of the others. Many new specialties--geophysics and biochemistry, for example--have resulted from combining the knowledge of two or more sciences.
The applied scientist ______.
A．is not always interested in practical problems
B．provides the basic knowledge for practice
C．applies the results of research to practice
D．does original research to understand the basic laws of nature
第5题
However, today, more and more consumers are choosing" green" and demanding that the products they guy should be safe for the environment. Before they buy a product, they ask questions like these:" Will this shampoo damage the environment?" "Can this metal container be reused or can it only be used once?"
A recent study showed that two out of five adults now consider the environmental safety of a product before they buy it. This means that companies must now change the way they make and sell their products to make sure that they are "green", that is, friendly to the environment.
Only a few years ago, it was impossible to find green products in supermarkets, but now there are hundreds. Some supermarket products carry labels (标签)to show that the product is green. Some companies have made the manufacturing(生产) of clean and safe products their main selling point and emphasize it in their advertising.
The concern for a safer and cleaner environment is making companies rethink how they do business. No longer will the public accept the old attitude of "Buy it, use it, throw it away, and forget it". The public pressure is on, and gradually business is cleaning up its act.
What has caused the pollution problem?
A．Careless methods of production.
B．Lack of consumer demand for environment friendly products.
C．Millions of tons of glass, paper, plastic and metal containers are produced.
D．Both A and B
第6题
Although it is true that many people carry guns legally in the United States, it is also known that many who possess guns carry them illegally. Others, who don't have guns, feel that guns can be acquired quite easily. A recent survey indicated that many high school students, especially in the inner cities, can acquire a gun with little difficulty, Some schools require students to pass through a metal detector similar to those found at airports before entering the school building.
Police statistics also show that death by firearms is one of the leading causes of death among children under twenty and many citizens feel that owning one is a necessary for self-protection. In a campaign to get children to give up their weapons, guns were once exchanged for toys at Christmas. Several years ago thousands of children handed in their firearms for coupons(赠券) redeemable(可赎回的) at Toys "R" Us. This was a bizarre and ironic indication of the full extension of the problem.
Also, some ranchers in rural areas who raise cattle and sheep feel they need to protect their animals against the mountain lions and wolves which attack their herds and flocks at night. To defend and support their rights to possess firearms The National Rifle Association (NRA) was founded in 1871 by National Guard officers. Their purpose was to help rifle owners to increase the accuracy of their marksmanship(枪法). The organization has close ties with the Defense department, which has helped to support the organization and even sponsor a rifle contest. Nevertheless, the main importance of this association has been its efforts to prevent strict gun control legislation. The association has great political support in small towns and rural areas especially in the West and the South where hunting is especially popular. Those who favor the right to possess guns insist that the second amendment to the constitution provides the right of people "to keep and bear arms." They believe that gun control laws will not solve the problem of crime and violence in America.
How do some schools check to see if students are carrying guns?
A．The administration searches their lockers.
B．They have employed security guards on every floor.
C．They have installed metal detectors at the entrance of the building.
D．They invite the police to make surprise search for guns.
第7题
The first question is how best to separate clean element—glass containers, plastics, and some paper and metal containers that is relatively clean when discarded—from mixed refuse. This clean element is the main target for Britain's recyclers. The method of collection is important because manufacturers will not reuse collected material unless it is clean and available in sufficient quantities. A bewildering assortment of different collection schemes operates in the rest of Europe, and pilot schemes are now under way in many British cities.
A realistic target for recycling mixed refuse is somewhere between 15 and 25 percent by weight, according to researchers at the Department of Trade and Industry's Laboratory. Statistics compiled by researchers at the University of East Anglia show that Britain could almost halve the total weight of domestic waste going to landfill by a combination of "collect” schemes(such as doorstep collections for newspapers),"bring” schemes(such as bottle banks)and plants for extracting metals.
This estimate makes two important assumptions. One is that the government will bring in legislation to encourage the creation, of markets for products made from recycled materials, especially glass, paper and plastics. The other is that industry will continue to introduce new technology that will improve both the products and the techniques used to separate recoverable materials from mixed refuse.
Which of the following can serve as a proper title for the passage?
A．An Impossible Target
B．Government Assumptions
C．Recycling Britain
D．Categories of Britain's Waste
为了保护您的账号安全，请在“上学吧”公众号进行验证，点击“官网服务”-“账号验证”后输入验证码“”完成验证，验证成功后方可继续查看答案！
微信搜一搜
上学吧
微信搜一搜
上学吧
