Social change is more likely to occur in societies where there is a mixture of different kinds of people than in societies where people are similar in many ways. The simple reason for this is that there are more different ways of looking at things present in the first kind of society. There are more ideas, more disagreements in interest, and more groups and organizations with different beliefs. In addition, there is usually a greater worldly interest and greater tolerance in mixed societies. All these factors tend to promote social change by opening more areas of life to decision. In a society where people are quite similar in many ways, there are fewer occasions for people to see the need or the opportunity for change because everything seems to be the same. And although conditions may not be satisfactory, they are at least conventional and generally agreed.

    Within a society, social change is also likely to occur more frequently and more readily in the material aspects of the culture than in the non-material, for example, in technology rather than in values; in what has been learned later in life rather than what was learned early; in the less basic and less emotional aspects of society-than in their opposites; in the simple elements rather than in the complex ones; in form rather than in substance; and in elements that are acceptable to the culture rather than in strange elements.

    Furthermore, social change is easier if it is gradual. This is one reason why change has not come more quickly to Black Americans as compared to other American minorities, because of the sharp difference in appearance between them and white people.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    If you want to slow aging, you might want to eat less. This finding is good news—if you were a mouse. The researchers studied mice, not people.

    John Price and other researchers studied two groups of mice. One group was able to eat as much as it wanted. The researchers limited what the mice in the other group ate. Their diet had 35 percent fewer calories than the first group of mice.

    Price says the mice with the diet restrictions were “more energetic and suffered fewer diseases.” They were not just living longer but seemed to stay younger for a longer period of time.

    The researchers found that fewer calories slow down a natural mechanism in cells called ribosomes. Price explains that ribosomes are responsible for making important proteins in the cells. But with fewer calories, they slow down. This gives the cells more time to repair themselves.

    The researchers say ribosomes use from 10 to 20 percent of the cell's energy to make those proteins. Price wrote that “because of this, it is impractical to destroy an entire ribosome” when it starts to break down. However, “repairing individual parts of the ribosome on a regular basis enables ribosomes to continue producing high quality proteins for longer than they would otherwise. This top quality production, in turn, keeps cells and the entire body functioning well.”

    Price said, “ribosome is a very complex machine, like a car.” They need “maintenance to replace the parts that wear out the fastest. When tires wear out,” he explained, “you don't throw the whole car away and buy a new one. It costs less to replace the old tires.”

    “Food,” he said, “isn't just material to be burned—it's a signal that tells our body and cells how to respond.” Price said the findings help to explain how exactly our bodies age. And this may “help us make more educated decisions about what we eat.”

A Teenage Inventor

    The world could be one step closer to quick and inexpensive Ebola detection thanks to a teenager from Connecticut.

    Olivia Hallisey, a junior at Greenwich High School, was awarded $50,000 in the Google Science Fair for her new method that detects Ebola, a virus that causes bleeding from different parts of the body and usually causes death. Olivia's method is to ask patients to put their saliva (唾液) onto a testing card. The card changes color if the person is catching Ebloa. Present Ebloa tests take up to 12 hours and cost $1,000. Olivia's method, however, can be done just in 30 minutes for about $25. Besides, the sample (样本) doesn't have to be put in a refrigerator thanks to the silk material Olivia uses to produce the testing cards.

    Olivia was inspired to deal with this global problem after watching the news that more than 10,000 people died from Ebola in West Africa. She was particularly worried about the fact that, while the acts of involvement can improve survival rates, present detection methods are costly, time-consuming and require complex tools. Olivia got help from her science research teacher. She drew out directions from past research, and figured out detection systems that have proven to work with other diseases, including Lyme disease and yellow fever.

    "What affects one country affects everyone," Olivia told CNBC. "We have to work together to find answers to the huge challenges which cause harm to the global health." The Connecticut's teen, who hopes to become a doctor one day, was named the Google Science Fair winner in the competition of 20 competitors from across the globe. The fair is open to young people between the ages of 13 and 18 in most countries.

    Olivia hopes her success will inspire other girls interested in science and computers. "I would just encourage girls to try it in the beginning, and remind them that they don't have to feel naturally drawn or feel like they have a special talent for maths or science," she told CNBC, "but just really look at something they are interested in and then think how to improve something or make it more enjoyable or relate it to their interests."

    A group of graduates, successful in their careers, got together to visit their old university professor. Conversation soon turned into complaints about stress in work and life.

Before offering his guests coffee, the professor went to the kitchen and returned with a large pot of coffee and a variety of cups—porcelain, plastic, glass, crystal, some plain looking and cheap, some exquisite and expensive—telling them to help themselves to the coffee.

    When all the students had a cup of coffee in hand, the professor said: "If you noticed, all the nice looking expensive cups were taken up, leaving behind the plain and cheap ones. While it is normal for you to want only the best for yourselves, that is the source of your problems and stress. Be assured that the cup itself adds no quality to the coffee. In most cases it is just more expensive and in some cases even hides what we drink. What all of you really wanted was coffee, not the cup, but you consciously went for the best cups. And then you began eyeing each other's cups.

    Now consider this: Life is the coffee; the jobs, money and position in society are the cups. They are just tools to hold and contain life, and the type of cup we have does not define, nor change the quality of life we live. Sometimes, by concentrating only on the cup, we fail to enjoy the coffee God has provided us."

    God brews the coffee, not the cups. Enjoy your coffee!

    "The happiest people don't have the best of everything. They just make the most of everything."

    Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God.

    School days are supposed to be the best days of your life and part of that experience usually involves some unforgettable physical activities. I asked some people to give me their memories of what happened to them on the sports field and beyond, and this is what they told me.

    Cup winners

    When I was about ten, the football team from our year unexplainably made it to the cup final of the local schools' league. I say unexplainably because I only remember us losing nearly every match we played. Anyway, in the final I set up the winning goal, a brilliant cross to my mate David who headed the ball in just before the final whistle. I still have a photograph of the team holding the cup.

    Forest hike

    I remember having to lead a group of eight boys on a school expedition for the best part of two days when I was a teenager. Even though we got lost at one point, I managed to keep them all together and get them from one end of a large forest to the other and back by sheer(纯粹的)force of will. I was chosen to be the leader, I think, because I was the only one who knew how to read a map!

    When we arrived back at the campsite, we found out that all the other groups had cheated and hitched(搭便车)most of the way instead… I felt a bit stupid, but also rather proud of myself at the same time for having done it properly.

    Learning to swim, learning to drown

    I learned to swim comparatively late, I suppose. I was maybe nine years old but my brother had a painful experience which nearly put him off for life. We lived in the USA for a while and had access to a university pool where the coaches had trained the American Olympic team. In those days, though, their idea of teaching kids how to swim was to tie a can to their ankles with a bit of string, throw them in the deep end and shout "Swim!". I am surprised my brother survived at all. He could only have been about six at the time.

    Did you know that if you attach a weighed stick to the back of a chicken, it walks like a dinosaur?

    No, you did not know(or care to know) such things, but now you do! Thanks to this year's winners of the 12 Noel Prize! Now in is 251h year, the lg Nobel is the goofy younger cousin of the honored Nobel Prize. It applauds achievements in the fields of medicine, biology, physics, economies.literature.etc. Every September at Harvard University, awards are presented in 10 categories that change year to year, depending on - according to the organization - what makes the judges "laugh, then think".

    The ceremony officially begins when audience members launch paper airplanes at an assigned human target on the stage, then speakers only have 60 seconds to present their research. In previous year, the one-minute rule was imposed by a young girl - nicknamed Miss Sweetie Poo -who would go up to the platform and repeat the words: "Please stop, I'm bored." in a sharp tone until the speaker left the stage.

    Fortunately for candidates though, the Ig Informal Lectures are held afterwards on Saturday to give presenters more time to explain the crazy things they're working on.

    The research can seem more like the brainchildren of teenage boys than of respectable adults. Justin Schmidt won the physiology Ig for creating the "Sting(蛰) Pain Index," which rates the pain people fell after getting stung by insects. Smith pressed bees against 25 different parts of his body until they stung him. Five stings a day for 38 days, Smith concluded that the most painful sting locations were the nose and the upper lip. Ouch.

    As silly as they sound, not all of the Ig awards lack scientific applicability, A group of scientists from 12 different counties won in the medicine category for accurately diagnosing patients with appendicitis (阑尾炎) based on an unusual measurement: speed bumps(减速带) . They found that patients are more likely to have appendicitis if they report pain during bumpy car rides.

    All these weird experiments have just one thing in common. They're improbable. It can be tempting to assume that "improbable" implies more than that--implies bad or good, worthless or valuable, trivial or important. Something improbable can be any of those, or none of them, or all of them, in different ways. And what you don't expect can be a powerful force for not only entertaining science, but also for the boundary-pushing science we call innovation.