As a boy, Charles Robert Darwin(达尔文) collected anything that caught his interest: insects, coins and interesting stones. He was not very clever, but Darwin was good at doing the things that interested him.

    His father was a doctor, so Darwin was sent to Edinburgh to study medicine, and was planned to follow a medical career. But Charles found the lectures boring. Then his father sent him to Cambridge University to study to be a priest. While at Cambridge, Darwin's interest in zoology and geography grew. Later he got a letter from Robert FitzRoy who was planning to make a voyage around the world on a ship, the Beagle. He wanted a naturalist to join the ship, and Darwin was recommended(推荐). That voyage was the start of Darwin's great life.

    As the Beagle sailed around the world, Darwin began to wonder how life had developed on earth. He began to observe everything. After he was home, he set to work, getting his collection in order. His first great work The Zoology of the Beagle was well received, but he was slow to make public his ideas on the origin of life.

    Later Darwin and Wallace, another naturalist who had the same opinions as Darwin, produced a paper together. Darwin's great book “On the Origin of Species by Means of Natural Selection”(《物种起源》) appeared. It attracted a storm. People thought that Darwin was saying they were descended from monkeys. What a shameful idea! Although most scientists agreed that Darwin was right, the Church was still so strong that Darwin never received any honors for his work.

    Afterwards, he published another great work, The Descent of Man. His health grew worse, but he still worked. “When I have to give up observation, I shall die,” he said. He was still working on 17, April, 1882. He was dead two days later.

    A characteristic of American culture that has become almost a tradition is to respect the self-made man--the man who has risen to the top through his own efforts, usually beginning by working with his hands. While the leader in business or industry or the college professor occupies a higher social position and commands greater respect in the community than the common laborer or even the skilled factory worker, he may take pains to point out that his father started life in America as a farmer or laborer of some sort.

    This attitude toward manual (体力的) labor is now still seen in many aspects of American life. One is invited to dinner at a home that is not only comfortably but even luxuriously (豪华地) furnished and in which there is every evidence of the fact that the family has been able to afford foreign travel, expensive hobbies, and college education for the children; yet the hostess probably will cook the dinner herself, will serve it herself and will wash dishes afterward, furthermore the dinner will not consist merely of something quickly and easily assembled from contents of various cans and a cake or a pie bought at the near- by bakery. On the contrary, the hostess usually takes pride in careful preparation of special dishes. A professional man may talk about washing the car, digging in his flowerbeds, painting the house. His wife may even help with these things, just as he often helps her with the dishwashing. The son who is away at college may wait on table and wash dishes for his living, or during the summer he may work with a construction gang on a highway in order to pay for his education.

    Cheating is nothing new. But it's becoming a lot more sophisticated. Republican vice-presidential candidate Sarah Palin was caught out once. A photo taken after the speech she'd given on a "return to conservative principles" showed her left hand covered with crib notes. These included the words "energy, budget cuts, tax" and "lift Americans' spirits". The word "budget" had been crossed out. Video footage also showed her reading from her hand when asked what top three things a conservative-led congress should do. Writing notes on your hand is one way to cheat in an exam. But these days, it's a lot easier ... especially with the Internet.

    Anyone who wants to cheat in an exam can probably find the answers online. There are hundreds of sites offering solutions to all sorts of tests. And it's a lucrative business. One operator in Oregon made $700,000 in about nine months before his arrest. The owner of a website in Ohio pocketed more than $300,000. And a famous overseas site is estimated to sell about 146,000 sets of answers and take in about $10 million per year. Actually, getting hold of the exam answers isn't that hard. Some do the exam themselves and use button cameras or document-scanning pens to copy the tests. Others organize for a group to take tests repeatedly until they can memorize the entire exam between them. Others simply bribe exam administrators.

    At the moment, such business is booming. More and more companies now require their employees to take professional exams. And hundreds of businesses and trade organizations have introduced formal certification programs to measure employee skills. In the US alone, at least 2 million exams are taken every year for information technology certification. But employees also have to take exams for all sorts of professions from crane operators to court reporters to school bus drivers and financial planners. Test officials estimate that hundreds of thousands of test-takers have used the Internet to buy answers for professional tests. And a recent survey found that 28 percent of test centres had at least one cheating incident over the last five years. In one incident, tens of thousands of soldiers obtained answers to tests in a range of military skills.

    Many see this as a cause for concern. Many tests are for work in sensitive areas such as defence installations and hospitals. Now, how would you feel if you knew that the people in charge of the computers controlling nuclear weapons might have cheated in their tests, and may not really know what they're doing?

    Humans and many other mammals have unusually efficient internal temperature regulating systems that automatically maintain stable core body temperatures（核心体温）in cold winters and warm summers. In addition, people have developed cultural patterns and technologies that help them adjust to extremes of temperature and humidity（湿度）.

In very cold climates, there is a constant danger of developing hypothermia（低体温）, which is a life threatening drop in core body temperature to below normal levels. The normal temperature for humans is about 37.0℃. However, differences in persons and even the time of day can cause it to be as much as 6℃ higher or lower in healthy individuals. It is also normal for core body temperature to be lower in elderly people. Hypothermia begins to occur when the core body temperature drops to 34.4℃. Below 29.4℃, the body cools more rapidly because its natural temperature regulating system usually fails. The rapid decline in core body temperature is likely to result in death. However, there have been rare cases in which people have been saved after their temperatures had dropped to 13.9-15.6℃. This happened in 1999 to a Swedish woman who was trapped under an ice sheet in freezing water for 80 minutes. She was found unconscious, not breathing, and her heart had stopped beating, yet she was eventually saved despite the fact that her temperature had dropped to 13.7℃.

In extremely hot climates or as a result of uncontrollable infections, core body temperatures can rise to equally dangerous levels. This is hyperthermia. Life threatening hyperthermia typically starts in humans when their temperatures rise to 40.6-41.7℃. Only a few days at this extraordinarily high temperature level is likely to result in the worsening of internal organs and death.

Most young people enjoy some form of physical activity. It may be walking, cycling or swimming, or winter, skating or skiing. It may be a game of some form—football, hockey, golf or tennis. It may be mountaineering.

    Those who have a passion for climbing high and difficult mountains are often looked upon with surprise. Why are men and women willing to suffer cold and hardship, and to take risks on high mountains? This astonishment is caused, probably, by the difference between mountaineering and other forms of activity to which men give their leisure.

    Mountaineering is a sport and not a game. There are no man-made rules, as others, as there are for such games as golf and football. There are, of course, rules of a different kinds which would be dangerous to ignore, but it is this freedom from man-made rules that makes mountaineering attractive to many people. Those who climb mountains are free to use their own methods.

    If we compare mountaineering with other more familiar sports, we might think that one big difference is that mountaineering is not a “team game”. We should be mistaken in this. There are, it is true, no “matches” between “teams” of climbers, but when climbers are on a rock face linked by a rope on which their lives may depend, there is obviously teamwork.

    The mountain climber knows that he may have to fight forces that are stronger and more powerful than man. He has to fight the forces of nature. His sport requires high mental and physical qualities.

    A mountain climber continues to improve in skill year after year. A skier is probably past his best by the age of thirty. But it is not unusual for men of fifty or sixty to climb the highest mountains in the Alps. They may take more time than younger men, but they perhaps climb with more skill and less waste of efforts, and they certainly experience equal enjoyment.

Plants are very important to living things. Life can not go on if there are no plants. This is because plants can make food from air, water and sunlight. Animals and human beings can not make food from air, water and sunlight. Animals get their food by eating plants and other animals. Therefore, animals and human beings need plants to live. This is why we find that there are so many plants around us. 

If you look carefully at the plants around you, you will find that there are two kinds of plants: flowering plants and non-flowering plants. Flowering plants can make seeds. The seeds are protected by the fruits. Some fruits have one seed, some have two and some have many seeds. But a few fruits have no seeds at all. An example of a fruit without seeds is the banana fruit. 

Most non-flowering plants do not grow from seeds. Many of them grow from spores(孢子). Spores are very small. Some spores are so small and light that they can float in the air. We may say that spores are quite the same as seeds. When these spores fall on wet and shady places, they usually grow into new plants.