Dreams may be more important than sleep. Some people don't need much sleep. But we all need to dream, scientists say.

    Dreams take up about one quarter of our sleeping time. People have several dreams each night. Dreams are like short films. They are usually in color. Some dreams are like old films. They come to us over and over again. That may be because the dreamer is worrying about something. Dreaming may be a way of trying to find an answer.

    Some people get new ideas about their work from dreams. They could have been thinking about their work all day. These thoughts can carry over into dream. Sometimes we wake up with a good feeling from a dream. But often we can't remember the dream.

    Dreams can disappear quickly from memory. Too much dreaming can be harmful. The more we sleep, the longer we dream. The mind is hard at working when we dream. That is why we may have a long sleep and still wake up tired.

     We often read the Air Quality Index （空气质量指标） or AQI reported in the newspaper. The AQI helps us understand what the air quality around us means to our health. The AQI uses colors, numbers and words to tell us about the air. Let's see what these colors and numbers mean.

    Are you bored with your mobile phone? Is it too heavy? Does it take too long to send and receive text message? If your answer is “Yes”, then read on!

EXIT introduces you to the latest mobile phone in town—the Speed Set 12000! It has over 30 features（特点）and weighs less than 130 grams! It is designed in Italy and made in India. It has a special gold button at the front that allows you to take pictures while you are talking. That's right, you can now talk and take pictures at the same time!

    The Speed Set 1200 is even more convenient to use than the Speed Set 1001. Like the Speed Set 1001, it has voice mail and caller show function, but the 1200 model has a bigger memory, so you can send and receive longer voice mails. Not only that, the newer model recognizes the voice mails, so it can tell you who the caller is. Also, the Speed Set 1200 has a more powerful battery, so you can recharge(充电) faster. With this model, it only takes you thirty minutes to recharge.

    The Speed Set 1200 has been already widely used in Asia and Europe. It is very popular with students and business people, as it has an Internet function that allows you to get information about news, sports and entertainment in just a few seconds.

    In the past, mobile phones were widely used to keep in touch with other people, but with the new Speed Set 1200, you can not only use it as a phone but also use it as a mini computer. So, if you are thinking of getting a new mobile phone, choose the Speed Set 1200. It's not just a phone. It's also a computer. At 2800 yuan, it's the cheaper mini computer in town!

    Since ancient times, human beings have looked up at the night sky. Comets (彗星) and meteors (流星) flying through the blackness were seen as signs from the gods. They were used to tell the future of human lives.

    In 2013, a meteorite shower hit an area in Russia. It injured around 1,200 people. In ancient times, this would have been a strange and terrible experience. Today, thought, science offers simple explanations for the occurrence (事件).

    Meteorites are small pieces of debris (碎片) that float around in space. Sometimes, they come near a planet, such as Earth. When they enter our atmosphere, they often heat up and become very bright. This is why they are sometimes called “fireballs”. They are usually made of metals, such as iron (铁), and other minerals (矿物). The Russian meteorites were stony, with iron making up 10 percent of them.

    Meteorite showers, such as that in Russia, happen when a large meteor enters the Earth's atmosphere and, due to heat, breaks up into small parts. Most of these are very small — smaller than a grain of sand — and so don't even make it to the ground. But others can cause a lot of damage.

    The meteor in Russia weighed 10 tons when it entered our atmosphere, and broke up about 20-30 miles (30-50 km) above ground. The sky was filled with bright lights and loud noises. Many windows were broken. The damage cost Russia around 206 million yuan.

    Do you know why different animals or pests (昆虫) have their special colors? Colors in them seem to be used mainly to protect themselves.

    Some birds like eating locusts (蝗虫), but birds cannot easily catch them. Why? It is because locusts change their colors together with the change of the colors of crops(庄稼). When crops are green, locusts look green. But as the harvest time comes, locusts change to the same brown color as crops have. Some other pests with different colors from plants are easily found and eaten by others. So they have to hide themselves for lives and appear only at night.

    If you study the animal life, you'll find the main use of coloring is to protect themselves. Bears, lions and other animals move quietly through forests. They cannot be easily seen by hunters (猎人). This is because they have the colors much like the trees.

    Have you ever noticed an even stranger act? A kind of fish in the sea can send out a kind of very black liquid (液体)when it faces danger. While the liquid spreads over (散开), its enemies (敌人)cannot find it. And it immediately swims away. So it has lived up to now though it is not strong at all.