Have you seen Avatar《阿凡达》? It's a popular 3D movie, and you may have to wear 3D glasses to see it. The 3D glasses make the images(图像)from the movie look as if they were coming straight towards you. 

 More and more 3D movies are coming to theaters. Some say that 3D TV sets will come into our homes in the near future. 3D technology can make TV and movies are more exciting. However, people with eye problems may get headaches if they spend too much time watching 3D movies. Why?

When we look at an object(物体), each eye sees it at a different angle(角度). Our eyes send the two images to our brain(大脑), and the brain puts them together. 3D technology uses two film projectors(投影机). One projects a left-eye-image and the other projects a right-eye-image. 3D glasses allow us to see a different image in each eye. So, when we are watching a 3D movie, our brain can't put together the images sent to our eyes. The brain needs to work harder at “reading” the images. That makes it easier for people with eye problems to get dizzy(头晕的) or have headaches. A famous eye doctor said if your eyes can't focus(聚焦) on the same object at once, you will have trouble watching 3D movies.

    Do you know fish come out of eggs when they are born? After the little fish comes out of the egg, it eats the food in the egg. When it is big, it leaves the egg. It swims in the water. You can see the eyes and nose. Its ears are hidden in the head.

    Spree fish eat other fish. Some fish have small mouths and teeth and they often eat plants.

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    Air pollution is one of the most common types of pollution in the world nowadays. It is quite serious in many places, especially in big cities. It can do great harm to our environment such as making the earth warmer, causing acid rain or destroying the ozone layer. As for human beings, air pollution causes all kinds of breathing problems.

    There are several reasons for air pollution. Firstly, many cities have a lot of factories and there we need to make food, clothing and other things. Every year these factories pour millions of tons of smog into air. Secondly, power factories can also give out harmful air. For example, in 1986 there was a bad accident at a nuclear power station in Russia. A cloud of radiation crossed the whole Europe. It is said that 125,000 people died in Russia as a result of illnesses caused by this accident. Thirdly, there are more cars in cities now. Once they are out in the streets, they will take in fresh air and give out dirty gas. Besides, smoking cigarettes also makes air pollution worse as will as damaging(损害) our health.  

    "What? You too? I thought I was the only one." Have you ever said to someone? If so, you may have ended up becoming friends.

    It seems that similarity often helps form a friendship. Aristotle once said, "Some define (给……下定义) it (friendship) as a matter of similarity; they say that we love those who are like ourselves."

    Now, there are some scientific explanations for this idea. The scientists from the University of California said friends have similar brains, Scientific American reported.

    The scientists invited 42 university students to take part in a scientific test. Each student watched the same set of videos. At the same time, the scientists scanned (扫描) their brains and recorded their brain activities.

    According to their study, friends who watched the same videos reacted (反应) in similar ways. Similar parts of their brains lit up while watching the videos, especially the parts that were connected with motivation, learning and memory. However, people who weren't friends had different reactions to the same videos.

    "Having close friends whose brains react like ours may be rewarding because it reinforces (加强) one's own values, opinions and interests," lead scientist Carolyn Parkinson told Business Insider.

    But brain similarity is not the only thing that can result in a friendship. Scientists from the University of Leipzig, Germany, found that a friendship is also based on how physically close you are to someone. They did a scientific test on first-year college students who met in class for the first time. In this test, students who sat next to each other were more likely to become friends.

    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.