Have you ever had trouble sleeping in a new place?

    Lots of people do. And now researchers from Brown University in Rhode Island think they know why. They found that one-half of the brain "remains more awake" than the other half when people are trying to sleep in a new place.

The sleep findings were reported in Current Biology by Brown University. In their report, the researchers said many people report they have a harder time sleeping the first night at a hotel or other places outside their home. They call it "first-night influence". "In Japan they say, 'If you change your bed, you can't sleep,'" said Yuka Sasaki, one of the report's writers. "You don't sleep very well in a new place. We all know about it."

    The researchers measured brain waves (测量脑波) for 35 volunteers over two nights in a laboratory. The two nights were a week apart (间隔). They found during the first night the left half of the brain was more active than the right half. This was during the first deep-sleep period, the researchers said.

    Sasaki said a lot of questions remain.

    Researchers did not keep measuring brain waves all night long. So, they don't know if the left half keeps "watch" all night, or whether it "works in shifts (轮换) with the right half later in the night". They also do not know why the brain activity, at least during the first period of deep sleep, is always on the left half.

    For some, this research may be calming. It is good to know that our brain is "looking out for us" in a new place. But it may not help with sleep. That brain activity, at least according to this new research, makes it harder to get the sleep people need to wake up well rested in the morning.

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    You probably know many of the things that you can do with the hundreds of different muscles（肌肉） in your body. But have you ever thought about how the muscles in an animal's body are different from yours? An animal's muscles are made to do the things that are the most important for its life.

    Lions are hunters. They depend on their ability to catch other animals. Lions must be fast in order to catch their prey(猎物). The powerful muscles in their back legs allow them to run at speeds of more than 30 miles per hour. They can also jump a distance of more than 35 feet. The strong muscles in their front legs help them catch their prey.

    Snakes also use their muscles for hunting prey and for movement, but their muscles work in very different ways than lion's do. Because snakes do not have any legs, they use their muscles to push against the ground or other objects to move themselves forward. Their muscles also allow them to eat things that seem much too large. For example, a snake may eat an egg that is larger than the width of its body. How does this happen? The snake's strong neck muscles work together to push the egg down the mouth.

    The elephant's long nose has a lot of muscles. Scientist believe that the nose alone has more than 100, 000 muscles! This is because the elephant uses its nose much in the same way that people use their hands and fingers. Even though the nose is large, it can perform surprisingly tasks. For example, an elephant can pick up a tree by its roots or even to lift a baby elephant.

    The great muscles of these animals seem pretty unbelievable. But the muscles in your body work exactly the way you need them to. After all, it might be fun to be able to jump a distance of 30 feet, but as a human being, there is just not much need for it.

    Nobody knows how many different languages there are in the world. The most widely used language is English. It's used by business people, airline pilots all over the world. It's also the first language of sports and science. So it's very important for us to learn English.

    English is most widely spoken in the world, while Chinese has the largest number of speakers. There are not only over one billion people living in China, but also many Chinese people living outside China. You can find large or small groups of Chinese people living in almost every country in the world.

    There are some other important languages in the world, too. Chinese is of course very important, especially in Asia. Arabic is widely spoken in many parts of Asia and Africa. Russian is spoken both in Europe and Asia. French is widely understood, not only in Europe, but also in parts of Canada, Africa and Asia. Spanish has a growing number of speakers all over the world, especially in Central and South Africa.

    What language do people speak in the United Nations? There are so many different languages in the world, but they decide to use only six of them. They are Arabic, Chinese, English, French, Russian, and Spanish. Everything spoken or written in one language is translated into the other five.

    Some scientists say that animals in the ocean are increasingly threatened(威胁) by noise pollution caused by human beings. The noise that influences sea animals comes from a number of human activities. It is caused mainly by industrial underwater explosions(爆炸) , ocean drilling, and ship engines. Such noises are added to natural sounds. These sounds include the breaking of ice fields, underwater earthquakes, and sounds made by animals themselves.

    Decibels (分贝) measured in water are different from those measured on land. A noise of one hundred and twenty decibels on land causes pain to human ears. In water, a decibel level of one hundred and ninety five would have the same effect（效果）.

    Some scientists have proposed setting a noise limit （限度）of one hundred and twenty decibels in oceans. They have observed that noises at that level can frighten and confuse whales（鲸鱼）.

    A team of American and Canadian scientists discovered that louder noises can seriously injure some animals. The research team found that powerful underwater explosions were causing whales in the area to lose their hearing. This seriously affected the whales' ability to exchange information and find their way. Some of the whales even died. The explosions had caused their ears to bleed.

    Many researchers whose work depends on ocean sounds object to a limit of one hundred and twenty decibels. They say such a limit would mean an end to important industrial and scientific research. Scientists do not know how much and what kinds of noises are harmful to ocean animals. However, many scientists suspect that noise is a greater danger than they believed. It's time for them to take action to help ocean animals.

    Rubbish is a major kind of environmental pollution. Each person produces about 2kg of rubbish a day. We are making waste products faster than nature can break them down. And we are using up resources(资源)faster than they can he replaced(取代).

    This adds up to trouble for the environment. Where does all that rubbish go? What can be done to help dispose of(处理)rubbish? How can we make less rubbish?

    Rubbish isn't just the smelly rotting fruits, vegetables or meat that we throw away(抛弃) in our homes Those are only a small part of all tile stuff we throw away. We create other kinds of waste, in construction, mining and in our factories.

    Did you ever wonder what happens to your rubbish? Most is burned(燃烧)or buried in landfills(垃圾填埋场). Less than a quarter of our waste is recycled(回收).

    With a population of 1.3 billion(十亿), rubbish is a big problem for China. Chinese city create around 148 million tons of rubbish every year. The amount is growing at around 10 percent each year.

    Once we used about 3 billion plastic shopping bags everyday in China. The result was a great waste of resources and serious pollution. So we did something about that. Now we use more cloth bags and shopping baskets when we shop.

    In the coming years China will build waste-to-energy plants in cities to clean up the rubbish. But there's a lot more that needs to be done. And you can play a role.