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 atom
s 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. 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 |
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 |
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 |
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. |
In the US, people prefer waiting for a table to sitting with people they don’t know. This means a hostess may not seat a small group until a small table is available, even if a large one is. If you are sitting at a table with people you don’t know, it is impolite to light up a cigarette without asking if it will disturb them.
At American restaurants and coffee shops you are usually served tap water before you order. You may find the bread and butter is free, and if you order coffee, you may get a free refill.
Most cities and towns have no rules about opening and closing time for stores or restaurants, though they usually do make rules for bars. Especially in large cities, stores may be open 24 hours a day.
Serving in restaurants is often large, too large for many people. If you can’t finish your meal but would like to enjoy the food later, ask your waitress or waiter for a “doggie bag”. It may have a picture of a dog on it, but everybody knows you’re taking the food for yourself.
Supper and dinner are both words for the evening meal. Some people have “Sunday dinner”. This is an especially big noon meal.
Tips are not usually added to the check. They are not included in the price of the meal, either. A tip of about 15% is expected and you should leave it on the table when you leave. In some restaurants, a check is brought on a plate and you put your money there. Then the waiter or waitress brings you your change.Which statement is true?
| A．American people like sitting with people they don’t know. |
| B．A hostess always seats a small group at a large table. |
| C．American people never sit with people they don’t know. |
| D．American people will not light a cigarette if the people who sit at the same table mind their smoking. |
What is served before you order?
| A．Bread. | B．Butter. | C．Coffee. | D．Cold water. |
What do American people always do when servings are too large for them?
| A．They take the food home with a “doggie bag” for their dogs. |
| B．They leave the food on the table and go away. |
| C．They take the food home with a “doggie bag” and enjoy the food later. |
| D．They ask the waitress or waiter to keep the food for them. |
What can you learn about “tips” according to the passage?
| A．Customers often add tips to their check. |
| B．The price of the meal usually includes the tip. |
| C．People are not expected to pay tips in addition. |
| D．Tips are supposed to be left on the table when customers leave |
Do you like chocolate? Maybe most people do. A box of it can be a great gift. Buy one for a friend and give it as a surprise. See how happy that person gets.
Say you just got a box of chocolate. Which piece do you pick first? A man has studied people’s choices. He says they tell something about the person. Did you choose a round piece? You are a person who likes to party. Did you choose an oval (椭圆形的) shape? You are a person who likes to make things. Picking a square shape shows something else. The person is honest and truthful. You can depend on him or her.
What kind of chocolate do you pick? Maybe you like milk chocolate. This shows you have warm feelings about the past. Dark chocolate means something else. A person who chooses it looks toward the future. What about white chocolate? Would you choose it? If so, you may find it hard to make up your mind. Some people like chocolate with nuts. These are people who like to help others.
Do you believe these ideas? Can candy tell all these things? It doesn’t really matter. There is one sure thing about eaters of chocolate. They eat it because they like it.This passage mainly tells us ______.
| A．why people like chocolate |
| B．almost everyone likes chocolate |
| C．about different kinds of chocolate |
| D．different choices may show different characters |
Picking a round shape of chocolate shows that a person ______.
| A．can be depended on |
| B．likes singing, dancing and drinking |
| C．is good at making things |
| D．likes to do something for others |
From this passage we can say that a helpful man may choose chocolate ______.
| A．with nuts | B．with coffee |
| C．in square shape | D．in oval shape |
The last paragraph suggests that the writer ______.
| A．believes all the information about chocolate |
| B．does not believe the information about candy |
| C．is trying to get you to believe these information |
| D．doesn’t think it important whether you believe the ideas |
In 2006, a large number of new Internet sites became popular around the world. Some of these are for communication, others for entertainment(娱乐).
The blog is one form of communication that increased in popularity. Through these personal websites(网址), people can share their lives, ideas and opinions on the Internet. People of all ages have their own blogs. For young people, they are a way to show their writing and other forms of self-expression. Blogs also connect people with other people who have the same interests. For example, teachers use blogs to share ideas with other teachers’, as well as experiences and concerns about their work.
YouTube is another Internet site that became more popular last year. This website lets anyone create, share and watch short videos. These include videos of people singing or dancing, or animals doing funny things. Three young men created YouTube almost two years ago as a personal video sharing service. They recently sold it to Google for more than one and a half billion dollars.
Games and entertainment also became a larger part of the Internet last year. One Internet social site is called Second Life. It is an online world in which computer users create a new self and live a different life. They get married, build homes, operate businesses, buy and sell goods, work, play and attend school.
People also take part in fantasy sports leagues with the help of the Internet. A fantasy sport is a game in which each member of a group acts as the owner of a team. Each owner creates a team of real-life professional players to compete against other teams in the league. More than fifteen million American adults play fantasy sports. The industry earns more than one billion（十亿）dollars each year from publications, memberships and other costs.The passage is mainly about __________.
| A．the most popular Internet technology in 2006 |
| B．some new ways for people to communicate or have fun on the Internet |
| C．one online game called Second Life |
| D．the high price of playing online |
Who is the owner of YouTube now?
| A．Three young men. | B．Google. |
| C．Computer users. | D．Yahoo. |
Whom does the underlined word “they” in Paragraph 4 refer to?
| A．The people who are interested in blogs. |
| B．The people who play games on YouTube. |
| C．The people who play Second Life. |
| D．The people who are created in Second Life. |
What do we know from the passage?
| A．Teachers can share ideas, experiences and concerns about their work with other teachers on any website. |
| B．More than fifteen million American teenagers play fantasy sports. |
| C．Second Life helps people get married, buy and sell goods, work, play and attend school in real life. |
| D．Fantasy sports, a game in which each member of a group acts as the owner of a team, is very popular around the world. |
The average American child spends three to five hours a day watching TV. In 1961, the average child began to watch television at age three; however, today it is nine months. Yet, most parents think that television has bad influence on their children. For example, in the early 1970s, my parents believed that my bad eyesight was the result of sitting too close to the screen, and they therefore made my stay at least six feet from it. Today, most people have no such worry, but many new ridiculous (荒谬的) sayings have appeared:
*TV makes kids stupid. Many children watch more educational programs when they are pre-schoolers. When they grow up, they can read more books and have much better ideas to solve difficult problems than other children.
*TV makes kids violent. The real story is not so simple. Hundreds of studies show that watching violence on TV makes children more aggressive (好斗的). But a study of over 5,000 children also finds that some positive programs make children kinder. The problem is that kids are increasingly watching shows with violence instead of those suitable for their age.
*Sitting around watching TV makes kids overweight. An experiment finds that when children watch less television, they do lose extra weight; however, reducing their television time does not make them more active. The real problem lies in snacking (吃零食). A widespread habit for kids, and junk-food advertisements.
*TV helps kids get to sleep. The opposite is true. The more television children watch, the more likely they are to have irregular sleep and nap(小睡) patterns. Allowing kids to watch television is part of the problem, not the solution.Which one is the advantage of educational TV programs?
| A．They will make children solve difficult problems better than others. |
| B．they will improve children’s ability to get along with others. |
| C．They are likely to make children more aggressive. |
| D．They will make sure of children’s success in the future. |
Why are children spending much time watching TV likely to be fat?
| A．Watching TV makes children lazy and inactive. |
| B．Children are attracted by the food advertisement on TV. |
| C．Watching TV doesn’t burn up as much fat as doing sports. |
| D．Children like to snack while watching TV. |
What influence does watching TV have on a child’s sleep?
| A．Children are likely to sleep deeper after watching TV. |
| B．Children’s sleep time will be greatly reduced. |
| C．It will make children form a bad habit of sleeping. |
| D．It will make children sleep easier. |
What is the purpose of this text?
| A．To increase people’s knowledge of watching TV. |
| B．To warn parents of the disadvantages of watching TV. |
| C．To explain the bad influences that watching TV has on children. |
| D．To correct parents’ wrong ideas of television’s effect on children. |
IN the famous fairy tale, Snow White eats the Queen’s apple and falls victim to a curse; in Shakespeare’s novel, Romeo drinks the poison and dies; some ancient Chinese emperors took pills that contained mercury, believing that it would make them immortal, but they died afterward.
Poison has long been an important ingredient in literature and history, and it seems to always be associated with evil, danger and death. But how much do you really know about poison?
An exhibition, the Power of Poison, opened last month at the American Museum of Natural History in New York, intended to give the audience a more vivid understanding of poison. The exhibition will continue until Aug 2014, reported The New York Times.
The museum tour starts in a rainforest setting, where you can see live examples of some of the most poisonous animals: caterpillars, frogs and spiders. Golden poison frogs, for instance, aren’t much bigger than a coin, but their skin is covered in a poison that can cut off the signaling power of your nerves, and a single frog has enough venom to kill 10 grown humans.
The exhibition also features interactive activities. In an iPad-based game, visitors are presented with three puzzling illnesses and asked to identify the poisons based on symptoms. In one case, for example, a pet dog is found sick in a backyard and visitors have to figure out whether it was the toad (蟾蜍), the leaky batteries in the trash or the dirty pond water that did it.
“Poisons can be bad for some things,” Michael Novacek, senior vice president of the museum, told NBC News. “Yet they can also be good for others.”
This is what visitors learn from the last part of the exhibition, which displays how poisons can be used favorably by humans, including for medical treatment.
The blood toxins of vampire bats, for example, can prevent blood from clotting (凝结), which may protect against strokes. A poisonous chemical found in the yew tree is effective against cancer, which is what led to the invention of a cancer-fighting drug called Taxol. One chemical in the venom of Gila monsters can lower the blood sugar of its victims, so it has been used to treat diabetes.
The benefits from natural poisons are not limited to just medicine. Believe it or not, many substances that we regularly take in – chili, coffee and chocolate, etc. – owe their special flavors or stimulating effects to chemicals that plants make to poison insects.By mentioning Snow White and Romeo at the beginning of the story, the author intends to____________.
| A．show that poison has long been involved in literature |
| B．show that poison is always linked with evil and death |
| C．draw readers’ attention to the topic of the article |
| D．get readers to think of more examples of the use of poison in stories |
What is the main purpose of the exhibition The Power of Poison?
| A．To give people more in-depth knowledge about poison. |
| B．To teach people how to handle poisonous animals. |
| C．To inform people about which animals are the most poisonous. |
| D．To show how poison has been used for medical treatment. |
Which of the following statements about the exhibition is TRUE according to the article?
| A．The exhibition will lead visitors to a real rainforest. |
| B．Golden poison frogs are the most poisonous animals on display. |
| C．Those who visit the exhibition can join in some iPad-based interactive games. |
| D．Visitors can listen to lectures on recent studies of poisonous animals. |