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.
The following is a recent survey among teenagers:
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Radio Most teenagers nowadays are not regular listeners to radio. They may occasionally tune in, but they do not try to listen to a program specifically. The main reason teenagers listen to the radio is for music, but now with online sites streaming music for free they do not bother, and users can choose the songs they want instead of listening to what the radio presenter/DJ chooses.
Television Most teenagers watch television, but usually there are points in the year where they watch more than average. This is due to programs coming on in seasons, so they will watch a particular show at a certain time (as long as it lasts) but then they may watch no television for weeks. Teenagers are also watching less television because of services such as BBC iPlayer, which allows them to watch shows when they want. Whilst watching TV, adverts come on quite regularly (18 minutes of every hour) and teenagers do not want to watch these, so they switch to another channel, or do something else whilst the adverts run.
Newspapers No teenager that I know of regularly reads a newspaper, as most do not have the time and cannot be bothered to read pages and pages of text while they could watch the news summarized on the Internet or on TV.
Internet Every teenager has some access to the Internet, be it at school or home. Home use is mainly used for fun (such as social networking) whilst school (or library) use is for work. Most teenagers are heavily active on a combination of social networking sites. Facebook is the most common, with nearly everyone with an Internet connection registered and visiting >4 times a week. Facebook is popular as one can interact with friends on a wide scale. For searching the web, Google is the dominant figure, simply because it is well known and easy to use. Some teenagers make purchases on the Internet (on sites like eBay) but this is only used by a small percentage, as a credit card is required and most teenagers do not have credit cards. Many teenagers use YouTube to watch videos (usually anime which cannot be watched anywhere else) and some use it as a music player by having a video with the music they want to listen to playing in the background.
Mobile Phones 99pc of teenagers have a mobile phone and most are quite capable phones. Usually, teenagers only use their phones for texting, calling. Features such as video messaging or video calling are not used—because they are expensive. Services such as instant messaging are used, but not by everyone. It usually depends whether the phone is Wi-Fi compatible, because otherwise it is very expensive to get Internet off the phone network. As most teenagers’ phones have Bluetooth support, and Bluetooth is free, they utilize this feature often. Mobile email is not used as teenagers have no need; they do not need to be connected to their inbox all the time as they don’t receive important emails. |
1. The survey carried out recently is mainly concerned with ______.
A. how teenagers consume media
B. what electric devices teenagers favor
C. which new trend teenagers are following
D. how teenagers contact others and make their social net
2. As is mentioned in the survey, the reason why teenagers watch less TV mainly lies in that ______.
A. teenagers do not watch regular programs
B. all the TV programs are on for only a few weeks
C. teenagers may turn to other devices to watch their favorite
D. the TV adverts coming on every channel are just the same
3. Which of the following is TRUE according to the survey?
A. Radio presenter or DJ used to invite the listeners to choose the songs they want.
B. The main source for teenagers to get news is Internet as well as newspapers.
C. Google is the most common social networking sites due to its convenience.
D. Some features of modern mobile phones are not widely used by teenagers.
John and Bobby joined a wholesale company together just after graduation from college the same year. Both worked very hard. After several years, however, the boss promoted Bobby to the position of manager but John remained an ordinary employee. John could not take it any more, tendered his resignation to the boss and complained the boss did not know how to delegate and did not value hard-working staff, but only promoted those who flattered him.
The boss knew that John worked very hard for the years. He thought a moment and said, “Thank you for your criticism, but I have a request. I hope you will do one more thing for our company before you leave. Perhaps you will change your decision and take back your resignation.”
John agreed. The boss asked him to go and find out anyone selling watermelon in the market. John went and returned soon. He said he had found out a man selling watermelon. The boss asked how much per kg. John shook his head and went back to the market to ask and returned to inform the boss $1.2 per kg.
Boss told John to wait a second, and he called Bobby to come to his office. He asked Bobby to go and find anyone selling watermelon in the market. Bobby went, returned and said, “Boss, only one person selling watermelon. $1.2 per kg, $10 for 10kg, he has inventory (清单) of 340 melons. On the table 58 melons, bought from the South two days ago, they are fresh and red, good quality.”
John was very impressed and realized the difference between himself and Bobby. He decided not to resign but to learn from Bobby.
Chances exist in the daily details. For the same matter, a more successful person sees more and farther so that he can find out an opportunity and catch it to realize his aim. If a person sees one year ahead, while another sees only tomorrow. Then the difference between a year and a day is 365 times!
1.Why did John decide to hand in his resignation to the boss?
A. Because he couldn’t stand being an ordinary employee.
B. Because Bobby would take John’s former position.
C. Because the boss was not flattered by his hard work.
D. Because Bobby instead of him was promoted.
2. What did the boss ask John to do?
A. To go to market and find out whether there is someone selling watermelons.
B. To make a complete marketing research on the various prices of watermelons.
C. To search for much information about the effective ways to sell watermelons.
D. To make a comparison on the prices of different types of watermelons.
3. What sort of following information about watermelons was NOT brought by Bobby?
A. The price. B. The quality.
C. The quantity. D. The weight.
4. From the difference of John and Bobby, we may infer that a more successful person is more _____.
A. alert, sensitive and passionate
B. observant, thoughtful and exploratory
C. considerate, modest and satisfied
confident, noble and tolerant
Directions: For each blank in the following passage there are four words or phrases marked A, B, C and D. Fill in each blank with the word or phrase that best fits the context.
As we all know, Chinese handwriting has infinite power to express differences of character and cultivation. But we have to admit that traditional handwriting has become a __50__ art, now that kids start using keyboards as soon as they begin school. However, writing things out by hand may be a __51__ way we train our brains, several studies suggest. Many psychologists think that handwriting can make you __52__!
Writing by hand is different from __53__ because it requires using strokes to create a letter, __54__ just selecting the whole letter by touching a key, says Virginia Berninger, a professor of psychology at the University of Washington. These __55__ movements activate large regions of the brain __56__ in thinking, memory, and language. Handwriting helps children learn letters and shapes, improves their composition of ideas, and may also __57__ fine-motor skills development.
A study by Berninger found that in grades two, four, and six, children wrote more words, faster, and expressed more __58__ when writing essays by hand than when typing on a keyboard.
A separate study by researchers at Indiana University found that children who practiced printing by hand had more active__59__than kids who __60__ looked at letters.
It’s not just children who __61__ from writing things out by hand, says a study in the Journal of Cognitive Neuroscience. Adults learning a new language remember its __62__ better if they write them out by hand than if they produce them with a keyboard.
As more people __63__ their days on the computer, says neuroscientist P. Murali Doraiswamy of Duke University, “__64__ people in handwriting skills could be a useful cognitive exercise.”
1.A. charming B. dying C. mixing D. challenging
2.A. common B. critical C. classic D. standard
3.A. smarter B. calmer C. deeper D. quicker
4.A. clicking B. talking C. typing D. moving
5.A. in addition to B. rather than C. except for D. other than
6.A. body B. eye C. letter D. finger
7.A. ended B. led C. included D. involved
8.A. boost B. weaken C. decline D. prospect
9.A. meanings B. ideas C. information D. emotions
10.A. mood B. behavior C. fingers D. brains
11.A. simply B. rarely C. hardly D. specially
12.A. benefit B. keep C. result D. learn
13.A. rules B. sounds C. characters D. sentences
14.A. get B. waste C. spend D. rely
15.A. retreating B. returning C. repeating D. retraining
Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.
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A. priority |
B. getting |
C. needs |
D. put off |
AB. depends on |
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AC. satisfy |
AD. hungry |
BC. likely |
BD. slightly |
CD. motivation |
A person’s motivation is a combination of desire and energy directed at achieving a goal. Influencing someone’s motivation means __1__ him or her to want to do what you know must be done. A person’s motivation __2__ two things:
One is the strength of certain needs. For example, you are __3__, but you must have a task completed by a nearing deadline. If you are starving, you will eat. If you are __4__ hungry, you will finish the task at hand.
The other is the perception (感觉) that taking a certain action will help __5__ those needs. For example, you have two burning __6__— the desire to complete the task and the desire to go to lunch. Your perception of how you view those two needs will determine which one takes __7__. If you believe that you could be fired for not completing the task, you will probably __8__ lunch and complete the task. If you believe that you will not get into trouble or perhaps finish the task in time, then you will be more __9__ to go to lunch.
“Simpler” books are the foundation ______ students build a lifelong habit of reading and further the actual skill of reading for longer and stronger periods of time.
A. which B. upon which C. for which D. in which
