阅读理解

Light and Reflection

    Light is another type of wave that carries energy. A source of light (光源) such as the sun or a light bulb gives off light rays that travel away from the light source in all directions.

    A light ray is a narrow beam (光束) of light that travels in a straight line.

    Most objects around you do not give off light on their own. They can be seen only if the light from another source bounces off (反弹) them and into your eyes. The process of light hitting an object and bouncing off is called reflection.

    Look at the picture. The light is given off by the light bulb. Some of these light rays hit the page and are reflected (反射). The student sees the page when some of the reflected light rays enter the student's eyes.

    When a light ray hits a surface (表面) and is reflected, the reflected ray obeys the law of reflection. The angle of incidence (入射角) is always the same as the angle of reflection. This is the law of reflection. And this is true for any surface, no matter what material it is made of.

    Clean water is not only important for people to produce food, but necessary for our life However, many people in Asia and Africa don't have enough clean water to use The World Health Organization reports that almost 4 000 children die each day of dirty water or lack(缺乏)of water.

    Farmers use 70% - 85% 0f the world freshwater to produce food. People usually don't pay much attention to how much water industry(工业)uses, but you may be surprised to know that industry uses 59% of the water in developed countries.

    Home use takes up（占据）only 8% in the world. But as cities grow, more water will be used. The local government has to try to make people useless water. In 60% of European cities, people are saving water by using less. They even keep waste water for other use. In Australia, the government has encouraged people to collect rainwater and recycle water from showers for a second use, The US Environmental Protection Agency has made a water saving program to encourage families and businesses to check their water use and save more water. Scientists and the UN are looking for good water management as the key to solving the problem. We can all work together to protect our fresh water in our daily life.

    Over 80G of the ancient forests have already been destroyed. Thousand-year-old trees are cut down just to make everyday goods. More and more wild animals are in danger now. Wild animals are our friends, and we cannot live without them. If we take no action, more and more wild animals will disappear in the future. It is time for us to save and protect endangered animals. Then what can we do? Here are some steps.

    Step one: Find out what animals are living near your place. Spend some time learning about the animals.

    Step two: Help to build more nature reserves and other wilderness areas. Protecting the living areas of wild animals is one of the best ways to help protect endangered animals. You can raise money for them or spend some time helping build nature reserves.

    Step three: Buy foods and goods that are made from materials which do not harm endangered animals or their living areas.

    Step tour: Join a local Wild Animals Club. You can take action to protect wild animals. There are many global groups that try to call on people to protect the environment by changing people's ideas and behaviours. Children, teenagers, teachers and schools from all over the world can help to save the animals. Everyone can do a little to help them, and every little bit of help is important!

    Stop reading for a minute and think about what you see when you look up at the sky on a clear night. You probably see many stars(星星). Long long ago, farmers watch some stars to know when to plant their crops. Travellers did so to find their way in the dark. Today stars are still important to some people.

    Scientists find that most stars are very big. In fact some stars are so far away that it would take millions of years to get to them even by spaceship.

    Another thing we know today about stars is that some are made up of(由……组成) hot gases. The gases are so hot that they send out light. If you watch a star carefully, you may notice that it twinkles(闪烁) sometimes. As you may understand, light from a star must shine through the air before you can see the star. Air is always moving, it makes light from the star move back and forth. When the light moves, it makes the star twinkle. Stars also have different colours. The colours of a star depend on how hot it is. To our surprise, the cool stars are red and the hottest stars are white.

    If you go shopping in any toy store, you can see clearly the differentgames and toys for boys and girls: there are a lot of pink toys on one side ofthe store for girls; and dark colored cars, guns, and soldiers for boys. Somebig stores with toys may even have a pink floor for girls and a blue floor forboys. In fact, it is difficult to buy a toy for a girl that is not pink.

    Somepeople think that too much pink is bad for girls. Sue Palmer, writer of ToxicChildhood, is very worried that most girls over the age of three are crazyabout the color. According to some scientists, this happens for two reasons. Firstly,most companies offer too many products in pink. Also, many parents think theirlittle daughter looks cute in pink. Sue Palmer says that girls at this agecannot make proper decisions by themselves, but the pink can affect (影响) the choices and thedecisions they will make in the future.

    Someparents are worried too-for example, Vanessa Holburn, thirty-two, who has twogirls under the age of four. Their bedrooms are a sea of pink and Vanessa isnot happy. "Pink says that you are soft and gentle. Blue says that you arestrong and powerful. I want my daughters to be strong and powerful. I'm worriedthat pink will not help them with that,"she says.

    Butnot everyone thinks there's something wrong with pink. Grayson Turner is afather of three girls and he isn't worried at all. "People forget thatthings change all the time," he says. "My girls used to love pink whenthey were little, but as they get older, they change." Turner explainsthat his twelve-year-old daughter never wears pink clothes anymore. "Thislove of pink is just a fashion and all fashions change," he adds. "It'sonly since the 1940s that people have started dressing girls in pink-beforethat it was a color for boys."