The definition of the standard kilogram is fundamentally imperfect. Getting the definition right is a challenge that has tried the patience and intelligence of scientists for decades.
Scientists use just seven basic units to define all the other quantities we use --- quantities such as speed, density, or electric power. All of those basic units except the kilogram are themselves defined in terms of natural properties that are beyond human control.
For example, the standard second (time) is defined as a specific number of vibration of a type of radiation released by atoms of a special metal. The standard meter (length), in turn, is defined as the length of the path light travels in a vacuum during a specific fraction of a second.
Not so the kilogram. This orphan of the basic unit family is simply the mass of a small platinum-iridium alloy cylinder (铂-铱合金筒) locked away by the international Bureau of Weighs & Measures in France.
Embarrassingly, the last time the copies were brought for a checkup in the 1980s, officials found that some copies had gained about 20 parts per billion in weight compared to the master cylinder since the previous checkup in the 1940s. This implies that the master cylinder itself may be an inconstant standard.
No one knows what causes the weight changes. But the uncertainty can’t be tolerated when precision(精密度) in research and some manufacturing now demands accuracy to a few parts per billion.
Several efforts in several different countries are under way to redefine the kilogram in terms of basic physical quantities such as counting the actual number of atoms of a specific substance in a kilogram or the electromagnetic force that balances a kilogram mass against gravity.
A project of the latter type at the NIST laboratories in Gaithersburg hopes eventually to define mass in terms of electrical units. So far, none of these redefinition projects has borne fruit. They require precision of measurement and control of experimental conditions. The slightest pollution, tiny vibrations, or other influences --- even changes in weather --- can ruin results. You’ve got to hand it to scientists who are willing to devote many years to such painstaking but fundamentally important research.
1.Which of the following best paraphrases the sentence “Not so the kilogram.” in paragraph 4?
A.The kilogram is not as accurate as the standard second.
B.The kilogram is not universally accepted in the world.
C.The kilogram is not defined in terms of natural properties.
D.The kilogram is not well defined as time and length.
2.Which of the following can NOT be concluded from the passage?
A.Experiments are being carried out to redefine the kilogram.
B.The uncertainty in the standard kilogram can seriously affect some research.
C.The redefinition of the standard kilogram is quite complicated.
D.Scientists will achieve success in redefining the kilogram in the near future.
3.According to the passage, to define the weight of mass in terms of electrical units _______.
A.is one of the best methods to redefine the kilogram
B.has been accepted as the only possible redefinition project
C.is not as simple as what people can understand
D.has been considered by some scientists as a better approach
4.We can know from the passage that the redefinition of the kilogram is _________.
A.more important in keeping market honesty
B.worth years of scientists’ painstaking research
C.the urgent requirement of business and manufacturing.
D.bring about important and fruitful results
高三英语阅读理解中等难度题
The definition of the standard kilogram is fundamentally imperfect. Getting the definition right is a challenge that has tried the patience and intelligence of scientists for decades.
Scientists use just seven basic units to define all the other quantities we use --- quantities such as speed, density, or electric power. All of those basic units except the kilogram are themselves defined in terms of natural properties that are beyond human control.
For example, the standard second (time) is defined as a specific number of vibration of a type of radiation released by atoms of a special metal. The standard meter (length), in turn, is defined as the length of the path light travels in a vacuum during a specific fraction of a second.
Not so the kilogram. This orphan of the basic unit family is simply the mass of a small platinum-iridium alloy cylinder (铂-铱合金筒) locked away by the international Bureau of Weighs & Measures in France.
Embarrassingly, the last time the copies were brought for a checkup in the 1980s, officials found that some copies had gained about 20 parts per billion in weight compared to the master cylinder since the previous checkup in the 1940s. This implies that the master cylinder itself may be an inconstant standard.
No one knows what causes the weight changes. But the uncertainty can’t be tolerated when precision(精密度) in research and some manufacturing now demands accuracy to a few parts per billion.
Several efforts in several different countries are under way to redefine the kilogram in terms of basic physical quantities such as counting the actual number of atoms of a specific substance in a kilogram or the electromagnetic force that balances a kilogram mass against gravity.
A project of the latter type at the NIST laboratories in Gaithersburg hopes eventually to define mass in terms of electrical units. So far, none of these redefinition projects has borne fruit. They require precision of measurement and control of experimental conditions. The slightest pollution, tiny vibrations, or other influences --- even changes in weather --- can ruin results. You’ve got to hand it to scientists who are willing to devote many years to such painstaking but fundamentally important research.
1.Which of the following best paraphrases the sentence “Not so the kilogram.” in paragraph 4?
A.The kilogram is not as accurate as the standard second.
B.The kilogram is not universally accepted in the world.
C.The kilogram is not defined in terms of natural properties.
D.The kilogram is not well defined as time and length.
2.Which of the following can NOT be concluded from the passage?
A.Experiments are being carried out to redefine the kilogram.
B.The uncertainty in the standard kilogram can seriously affect some research.
C.The redefinition of the standard kilogram is quite complicated.
D.Scientists will achieve success in redefining the kilogram in the near future.
3.According to the passage, to define the weight of mass in terms of electrical units _______.
A.is one of the best methods to redefine the kilogram
B.has been accepted as the only possible redefinition project
C.is not as simple as what people can understand
D.has been considered by some scientists as a better approach
4.We can know from the passage that the redefinition of the kilogram is _________.
A.more important in keeping market honesty
B.worth years of scientists’ painstaking research
C.the urgent requirement of business and manufacturing.
D.bring about important and fruitful results
高三英语阅读理解中等难度题查看答案及解析
The definition of the standard kilogram is almost entirely wrong. Getting that definition right is a challenge that has tried the patience and intelligence of scientists for decades.
Scientists use just seven basic units to define all the other quantities we use — quantities such as speed or electric power. All of those basic units except the kilogram are themselves defined according to natural properties（属性）that are beyond human control.
For example, the standard second (time) is defined as a specific number of vibration（振动）of a type of radiation sent out by atoms of a special metal. The standard metre (length), in turn, is defined as the length of the path light travels under certain conditions.
Not so the kilogram. This orphan of the basic unit family is simply the mass of a small platinum-iridium alloy cylinder（铂—铱合金筒）locked away in a container maintained by the International Bureau of Weights & Measures in Sevres, France, near Paris. Official bodies around the world have copies of the cylinder.
Embarrassingly, the last time the copies were brought to Sevres for a checkup in the 1980s, officials found that some copies had gained about 20 parts per billion in weight compared to the master cylinder since the previous checkup in the 1940s. This implies that the master cylinder itself may be an inconstant standard.
Several efforts in several different countries are under way to redefine the kilogram according to basic physical quantities such as counting the actual number of atoms of a specific substance in a kilogram or the electromagnetic（电磁的）force that balances a kilogram mass against gravity. A project of the latter type at the laboratories in Gaithersburg, Md., hopes eventually to define mass by means of electrical units.
So far, none of these redefinition projects has borne fruit. They require the very accuracy of measurement and control of experimental conditions. The slightest influence — even a tiny change in weather — can ruin results. You’ve got to hand it to scientists who are willing to devote many years to such painstaking — but extremely important — research.
1. Compared with other basic units, the kilogram is ____.
A. as accurate as other basic units
B. not universally accepted in the world
C. not defined according to natural properties
D. defined in the same way as other basic units
2.The author introduced the examination of copies of a platinum-iridium alloy cylinder in the 1980s to indicate that ____.
A. the causes of weight changes had been found
B. such kind of checks had been carried out regularly
C. the changes in weight challenged the definition of the kilogram
D. the consequences of such changes were great in research
3. According to the passage, to define the weight of mass by means of electrical units ____.
A. is the only way to redefine the kilogram scientifically
B. has been accepted as the only possible redefinition project
C. is not as complicated as people understand
D. has been considered by some scientists as a better approach
4. Which of the following cannot be concluded from the passage?
A. Scientists will achieve success in redefining the kilogram in the near future
B. Some scientists are trying to redefine the kilogram according to basic physical quantities.
C. The redefining of the standard kilogram is quite complicated and can be affected by a number of factors.
D. A number of experiments are being carried out to redefine the kilogram.
高三英语阅读理解中等难度题查看答案及解析
One of the most fundamental changes brought about in the last decade is the rise of remote learning. With the global climate crisis and health pandemics, remote learning has become even more relevant today. Schools, universities and corporates can continue affording education and training by remote technology in the time of social distancing due to the COVID-19 crisis. 1.
Learn Anywhere, Anytime
Gone is the need to be on campus at a specific time of day and remain there for the duration of numerous classes. 2.. More importantly, it has also made learning a practical choice for many rural communities who are unable to travel the vast distances to school every day and to remote teams working for companies located afar.
3.
When it comes to learning, one size doesn’t fit all People have varied learning styles that change depending on the nature of the content they are trying to absorb. E-Learning allows learners to personalize their education, focusing on areas that need greater attention in more detail. Also, rather than being a one-way path where the learner listens and takes in information, online training means that learners can pursue areas that interest them in more detail.
Better Engagement
Keeping learners engaged throughout the training is one of the key struggles. One of the strengths of E-Learning is the diverse nature in which the course content is delivered. 4. Some online learning communities allow trainers to provide multimedia recording to make training more engaging. With the game engine, they also have the option to gamify content and include rewards once sections are completed for young employees and fresh graduates who might have just passed out from school and are still transitioning to the corporate world. 5.
A.E-Learning gives people the flexibility to be able to learn at home, anytime they want.
B.Personalized Learning Experience
C.Learn more in detail
D.Learners are now used to and expect interactivity.
E.Nearly 30 percent of learners, or more than six million students, having taken at least one course online.
F.Overall, there are a few core reasons to opt (选择) for remote learning.
G.Quizzes, polls, and discussion boards also mean trainees get to discuss content and interact with one another.
高三英语七选五中等难度题查看答案及解析
The right to vote is one of the most fundamental rights of any democracy. Yet, for too long, too many of our fellow citizens were denied that right simply because of the color of their skin.
Fifty years ago this week, President Lyndon Johnson signed a law to change that. The Voting Rights Act broke down legal barriers that stood between millions of African Americans and their constitutional right to cast ballot(投票). It was, and still is, one of the greatest victories in our country’s struggle for civil rights. But it didn’t happen overnight. Countless men and women marched and organized, sat in and stood up, for our most basic rights. For this, they were called agitators(挑拨者) and un-American; they were jailed and beaten. Some were even killed. But in the end, they reaffirmed (重申)the idea at the very heart of America: that people who love this country can change it.
Our country is a better place because of all those heroes did for us. But as one of those heroes, Congressman John Lewis, reminded us in Selma this past March, “There’s still work to be done.” Fifty years after the Voting Rights Act, there are still too many barriers to vote, and too many people trying to erect（建立） new ones. We’ve seen laws that roll back early voting, force people to jump through hoops to cast a ballot or lead to legitimate (合法的) voters being improperly purged from the rolls. Over the years, we have seen provisions (规定) specifically designed to make it harder for some of our fellow citizens to vote. In a democracy like ours, with a history like ours, that’s a disgrace. That’s why, as we celebrate the 50th Anniversary of the Voting Rights Act, I’m calling on Congress to pass new legislation to make sure every American has equal access to the polls.
It’s why I support the organizers getting folks registered in their communities. And it’s why, no matter what party you support, my message to every American is simple: get out there and vote—not just every four years, but every chance you get, because your elected officials will only heed(留心) your voice if you make your voice heard. The promise that all of us are created equal is written into our founding documents but it’s up to us to make that promise real. Together, let’s do what Americans have always done: Let’s keep marching forward, keep perfecting our union, and keep building a better country for our kids.
[From Obama Weekly Address Aug 8th , 2015]
1.Many Americans were denied the right to vote simply because _____.
A. they were unwilling to go out and vote
B. they were agitators and un-American
C. too many people tried to erect new barriers
D. the color of their skin was different
2.What message does President Barack Obama want to convey in this speech
A. The President underlined that all people are created equal.
B. The President celebrated the 50th Anniversary of the Voting Rights Act.
C. The President reaffirmed the commitment to protecting the right to vote.
D. The President called on everyone to seize every chance to elect officials.
高三英语阅读理解中等难度题查看答案及解析
The most typical definition of success is “the accomplishment of an aim or purpose” or what most of us have heard: the attainment of popularity or profit. But is success really defined by purposes or profit?
After graduating from high school, my family advised me to aim to build a successful career. My options were narrowed down to becoming a doctor or choosing a field in engineering. So I graduated with a chemical engineering degree. I was advised to aim for graduate (研究生的) studies, and in less than two years, I had a highly specialized degree in plastics engineering from one of the most reputable universities in the U.S. Then I found a corporate job, performed well in the organization, climbed up the ladder (晋升的阶梯) and made a bigger paycheque with every new title. My proud parents told my story to the rest of the family and friends as a “success” story.
No matter where we live in the world, we all have our own versions of success. Our families take pride in telling the world how successful we are in our profession, and often the only measure of that success becomes the financial wealth we accumulate. In a world where everything is reflected by numbers—the likes on Facebook, the number of views on You Tube, etc—every aspect of our life is being taken over by numbers. We are conditioned to believe that the stronger your financial standing, the higher you rank on the success chart. But remember the words “aim” or “purpose,” in the definition of success. Altruistic figures such as Mother Teresa, Mahatma Gandhi and Martin Luther King Jr. also lived successful lives but had selfless concern over the well-being of others. While the rest of the world focused on accumulating wealth, they focused on giving, doing, and creating for everyone else.
Wealth alone never will be the measure of success. Think beyond profits. No promotion I ever received in my professional career was because of my deep desire to obtain a better title or higher pay; instead, it was based on the excellence I created in the experience our customers had with the organization.
1.What do you know about the author?
A. He has lived up to his family’s expectations.
B. He asks his parents for advice on everything.
C. He doesn’t like his job though he is well paid.
D. He wanted to be a doctor but became a chemical engineer.
2.What's the common awareness around the world?
A. Social connections. B. Contributions to society.
C. The accumulation of financial wealth. D. The accomplishment of personal dreams.
3.What does the underlined word “Altruistic” in Paragraph 3 mean?
A. Of abundant wealth.
B. Of few achievements.
C. Devoted to others’ welfare.
D. Focused on personal well-being.
4.What inspiration can be drawn from the author's working experience?
A. Change jobs frequently for higher pay.
B. Aim at providing quality service at work.
C. Take every chance to get promotion.
D. Focus on making profits from the customers.
5.What's the author’s purpose in writing this passage?
A. To explore the true meaning of success.
B. To express his inner voice to his parents.
C. To acknowledge the help he has received in his life.
D. To share his personal experience for others’ reference.
高三英语阅读理解中等难度题查看答案及解析
—Is that Dec．21,2012 is the end of the world true?
—Definitely not, but ______ must be paid to global climate change．
A．contact B．care C．attention D．influence
高三英语单项填空中等难度题查看答案及解析
The age of adulthood is by definition arbitrary. If everyone matured at the same, fixed rate, it wouldn’t be a human process. Indeed, maturation happens at varying speeds across different categories within the same individual, so I’d say I was easily old enough to vote at 16, but nobody should have given me a credit card until I was 32, and I’ve got the county court judgment to prove it.
However, we broadly agree that there's a difference between a child and an adult, even if we might argue about the transition point. So the political theorist David Runciman's view that six-year-olds should be allowed to vote goes against any standard argument about the age of civic responsibility. Nobody would say that a six-year-old could be held criminally responsible, could be sent to war, could be capable of consent, could be given responsibility for anything. So allowing them the vote-along with, unavoidably, seven-year-olds who are even sillier, if anything-is quite an amusing proposal.
Runciman's argument is that this is the only way to rebalance political life, which is currently twisted in favor of the old, who don't (he added) ever need to demonstrate mental capacity, even long after they've lost it.
The first part of his case is self-evident: pensions are protected while children's centers are closed, concepts such as sovereignty(最高权威) are prioritized over the far more urgent business of the future: climate change. Nostalgia(怀念) for a past the young wouldn't even recognize plays a central role, which is completely unfair.
Most of the arguments against giving six-year-olds a vote are that children would end up voting for something damaging and chaotic, if someone made unrealistic promises to them, which could never be realized.
Well, it's not children's fault.
Having said that, children do tend towards the progressive, having a natural sense of justice (which kicks in at the age of six months, psychologists have shown, by creating scenes of great unfairness to babies, and making them cry) and an underdeveloped sense of self-interest. My kid, when he was six, made quite a forceful case against private property, on the basis that, since everybody needed a house, they shouldn't cost money, because nobody would want anyone else not to have one. Also, food should be free. It was a kind of pre-Marx communism, where you limit the coverage of the market to only those things that you wouldn't mind someone else not having.
On that particular day, when we were registered as voters, my kid was quite far to the left of me, but in the normal run of things, we're united, which brings us to the point of the problem: children obey you on almost nothing, but they do seem to believe in your politics until they're adolescent. So giving kids the vote is really just a way of giving parents extra votes. And what can stop us having even more children, once there's so much enfranchisement(选举权) in it for us?
Now, if parents could be trusted to use their influence wisely, and hammer into children the politics it will take to assure a better future, then I wouldn't necessarily have a problem with that, apart from, obviously, that culture is already wildly twisted towards parents, and I can imagine a few non-parents boiling with fierce anger. But that's not worth talking about anyway, because parents can't be trusted, otherwise we'd all already vote Green(绿党).
In short: no, six-year-olds should not get the vote; but while we're here, if any votes come up in the near future, which will have an impact on the next five decades of British political life, alongside EU migrants,16-year-olds certainly should be enfranchised.
1.The author refers to his age of adulthood to prove that .
A.people mature at different rates in various aspects
B.there's a common standard for the age of adulthood
C.a credit card is more difficult to get than the vote
D.certain rights are granted at different stages of life
2.People reject David Runciman's proposal because .
A.they don't think a child can grow into adulthood earlier
B.they are uncertain whether children can assume responsibility
C.they believe children are far from mature in many ways
D.they know the age to get the vote is not to be questioned
3.The author talks about his kid to indicate that .
A.children are good-natured and like to help people in need
B.children are simple-minded and can fall for an adult's trick
C.children are innocent and don't want to be involved in politics
D.children are in favor of a just society and tend to be idealistic
4.The author thinks allowing children the vote may lead to .
A.twisted culture B.misuse of rights
C.parents' objections D.unusual maturation
5.What is the main point of the passage?
A.Allowing children the vote is not altogether absurd.
B.There is a difference between adults and children.
C.Parents should introduce politics to their children.
D.The definition of adulthood is quite controversial.
高三英语阅读理解困难题查看答案及解析
—Is that Dec.21,2012 is the end of the world true?
—Definitely not，but ________ must be paid to global climate change.
A．contact B．care
C．attention D．influence
高三英语单项填空中等难度题查看答案及解析
听下面一段独白，回答以下小题。
1.What is the definition of the “wealthy” people in the survey?
A. Those with over 1 million pounds in assets to invest.
B. Those with over l million pounds in estates.
C. Those with over I million pounds in stock market.
2.How many developed countries are involved in this survey including the U.K.?
A. 19. B. 20. C. Not mentioned.
3.Why does Iain criticize those who never want to retire on the Daily Mail website?
A. They never get satisfied.
B. They are wasting social resources.
C. They should not live to work.
4.What does Professor Sarah Harper say about people’s unwillingness of retirement?
A. Work gives them status.
B. Work makes them earn more money.
C. Work makes them respectable in their family.
高三英语短文困难题查看答案及解析
What is art? According to one definition, it is the creation of something that appeals to our sense of beauty. This definition may include painting, drawing, sculpture, and architecture, or performing arts such as music and drama. Cultural and historical influences, as well as one’s own consciousness of what is aesthetically(审美地 )pleasing, play a role in what one believes to be art. To some people, art is the description of an object--- a painting or sculpture of a person, for example. For others, art may be a blank canvas, or a piece of chalk.
In order to talk about the different artistic styles that have existed over time, art historians have classified these styles into different periods and organized them in chronological order. The works of art produced within each period mirror the culture and events of that time.
The earliest forms of art, from the prehistoric era(时代), include simple cave paintings and figures made from stone. These were followed by the sculptures and carvings of Ancient Civilizations era. Styles of the later Classical era (800 B.C. to 200 A.D.), reflect the culture of the time--- one that favored simplicity and balance. The period of the Middle Ages followed, and was succeeded by a revival（复兴） of classical styles in the Renaissance era, beginning around 1400. Well-known artists of this time include Michelangelo and da Vinci. One hundred years of Baroque style, and then fifty years of Rococo followed the 200-year Renaissance. The start of the nineteenth century saw the rise of the Premodern era, followed by the Modern era, a period that lasted until 1945. This was followed by Postmodern era that characterizes the present day.
In addition to differences in artistic styles between eras, there are also differences within each era. The Postmodern era, for example, has featured innovative（创新） artistic styles such as Pop Art ( which includes work by Andy Warhol), Minimalism, and Conceptualism. Since the 1960s, Conceptualism has grown in popularity. This style focuses more on the idea or ‘concept’ of art using realistic objects, rather than on art that is created using traditional materials such as paint, canvas, stone, or clay. Whereas Warhol used a can of beans as the basis for a painting, for example, a conceptual artist might say that the can itself is a work of art.
Conceptualism has become an increasingly controversial（有争议的） art style, particularly as result of numerous conceptual artists winning the Turner Prize. This ￡20,000 award is presented annually to a British artist under the age of fifty, in recognition of an outstanding work. Sponsored by the Tate Gallery of Britain, it is recognized as one of Europe’s most prestigious awards for visual arts. Its aim is to promote discussion about contemporary British art. In 2002, pop music icon Madonna presented the Turner Prize to conceptual artist Martin Creed.
1. One of the artistic styles that many people today discuss and arguing about is ______.
A. classic style B. Conceptualism C. Pop art D. Baroque style
2. Which statement is NOT true according to the passage?
A. Pop Art, Minimalism and Conceptualism are styles that developed in the Postmodern era.
B. Some of the world’s earliest art was created in caves.
C. History, culture and one’s concept of beauty affect what a person believes to be art.
D. Art historians refer to today’s artistic period as the Modern era.
3. According to the passage, art historians have classified these styles into ____ periods.
A. 7 B. 8 C. 10 D. 12
4.If the passage continues, the following paragraph will be probably about_________.
A. Martin Creed’s winning works B. Madonna’s outstanding art style
C. the status of Conceptualism D. the conclusion of art
高三英语阅读理解中等难度题查看答案及解析