As a result, songs sound like noise to an amusic. Many amuics compare the sound of music to pieces of metal hitting each other. Life can be hard for amusics. In fact, most people cannot understand what it feel like be amusic. Just going to a restaurant or a shopping center can be uncomfortable or even painful. That is why many amusics have to stay away from places where there is music. However, this can result in social loneliness. "I used to hate parties,"says Margaret, a seventy-year-old woman who only recently discovered that she was amusic. By studying people like Margaret, scientists are finally learning how to identify(辨别) this unusual condition.

  Scientists say that the brains of amusics are different for those of people who can enjoy music. The difference is complex(复杂的), and it is not connected with poor hearing. Amusics can understand other non-musical sounds well. They also have no problems understanding common speech. Scientists compare amusics to people who just can't see certain colors.

Many amusics are happy when their condition is finally diagnosed(诊断). For years, Margaret felt embarrassed about her problem music. Now she knows that she is not alone. That makes it easier for her to explain. "When people invite me to a concert, I just say "No, thanks. I'm amusic." says Margret.

    Every living thing on Earth is either a plant or an animal, right? Wrong! Many organisms（有机体）in our world are neither. Some of them float through the air, and some lie hidden in the ground. They do not need sunlight to survive, and if the weather becomes too cold, they can become inactive until conditions improve.

    What are these? They are called fungi(菌类), and you see them almost every day. Many kinds of fungi seem disgusting, such as the green black things that appear on the food which are left too long in the refrigerator. But other kinds are not so bad. For example, the yeast that is used to make bread and mushrooms (蘑菇) are both fungi.

    What makes fungi different from plants and animals? An animal can move around by itself. Fungi get around too, but they don't have feet, wings, or tails. They have to wait for wind or some other outside force to move them. Plants are different from fungi because they have chlorophyll（叶绿素）. It helps them make food from the energy in sunlight. Fungi do not have chlorophyll.

    Some fungi are bad, while others are not. Some fungi cause diseases, such as athlete's foot, which makes feet uncomfortable. Other kinds of fungi can be used to make medicines, which have saved many lives.

    Fungi clean up more than wounds, though. They are the world's first recyclers. Without fungi, our world would be a mess. Since fungi cannot make their own food as plants do, they must get their food elsewhere. Many fungi get their food from dead plants. They break them down and turn them into soil. The fungi get a meal, and the world gets a housecleaning.

    Animals can move from place to place, but plants cannot. When an animal is under attack, it can run away or fight back. Plants certainly cannot run away, and they have no teeth or claws. But plants can protect themselves in both physical and chemical ways.

    Some plants have their own ways to keep animals away. For example, the leaves of the holly(冬青) have sharp prickles(刺) that discourage grass-eating animals. Holly leaves on lower places have more prickles than leaves on upper places. This is because the lower leaves are easier for most animals to reach. Some plants, such as the oak trees(橡树), have thick and hard leaves that are difficult for animals to eat. Some grasses may contain a sandy material, and eating such grasses wears down the animals' teeth. Many plants also have chemical defenses. Some plants produce chemicals that taste bitter(苦) or cause an unpleasant reaction. Some plants may fight against an attack by increasing the production of these chemicals. When a worm bites a tobacco leaf (烟叶), the leaf produces a chemical smell. Many plants depend on both physical and chemical defenses. A certain plant in China, for instance, has prickly leaves, and each prickle has poisonous water(毒液). Only one experience with this kind of plant will teach an animal to stay away from it in the future.

    When we think of paper, we think of newspapers and books. But there are many other uses. Only half of the world's paper is used for books and newspapers.

    Paper is very good for keeping you warm. You have perhaps seen homeless men sleep on a large number of newspapers. In Finland, it is sometimes-40℃ in winter. The farmers wear paper boots(靴子)in the snow. Nothing could be warmer.

    Each year, more and more things are made of paper. We have had paper cups and plates for a long time. But now we hear that chairs, tables, and even beds can be made of paper. Besides paper boots and shoes, you can wear paper hats, paper dresses, and paper raincoats. When you have used them once, you may throw them away and buy new ones.

    The latest use of paper seems to be paper houses. These are not small houses for children to play in, but real, big houses for people to live in. You can buy a house with three rooms for about 500 dollars. You can put it up by yourself in a few hours, and you can use it for about five years.

    A few years after World War Ⅱ finished, scientists spoke with great eagerness about the use of nuclear power as a source of energy. Within twenty years, they said, nuclear would take the place of coal, gas and oil as a source of power at home and in industry. This promise has never been carried out(兑现)and there are serious doubts that it ever will be. Nuclear power plants are used to produce energy in some wealthier countries, but the cost is high.

    Although safety measures have been taken, radiation leaks have taken place and workers have been killed or affected. The problem of getting rid of the nuclear waste has proved most difficult. There is a limit to the amount of waste materials which can be buried in the ground or poured on the sea-bed. These methods may also cause more problems. Waste materials polluted by radiation may remain dangerous for 200 years or more.

    It is no surprise that scientists have now turned to the sun and the sea as sources of power. The sun shines day after day almost wastefully, providing us with energy far be yond all our needs.