Have you ever seen a horse with toes? Millions of years ago, horses had many toes. They had four toes on each front foot. They had three toes on each back foot. The horses were no bigger than cats.

    These small horses lived in the forest. Their many toes helped the horses run over the soft, wet ground.

    It was very hot in the forest. But the weather changed. It became cold. Many trees could not live in cold weather. The trees died and fell. Open fields took the place of forests. The sun made ground dry and hard.

    Horses began to change, too. They began to get bigger. This took a long time. On the dry, hard land, horses needed only their middle toes for running. Their middle toes became hard. After a long while, horses had only one hard toe on each foot. We call this hard toe a hoof.

    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.

    There was a world's advanced robot exhibition in Moscow. Over 20 skilled robot performers from all over the world took part in the exhibition.

    The exhibition was opened by British-born Titan, a world-famous dancing robot that had performed together with artists. Besides its quick moves, the robot is also known for its stand-up comedy and beautiful voice.

    Robot Hespin, a life-sized humanoid robot can make others happy. The robot not only sings and dances but also acts as a museum guide. It's very impressive. It can even hold conversations with humans.

    Then there is Cubic, an ordinary boxy robot that has been created to make our lives easier. It can read the latest news, switch off lights, and order pizza. Cubic can hold basic conversations and tell jokes.

    South Korea's friendly robots not only dance but also clean floors. Germany's famous metal rock band performs wonderfully.

    Most of the robots seem to have some kinds of dancing skills. The organizers say that their main purpose is to create a meeting place or a global platform to enable the people of Russia to experience some of the world's most advanced robots.

An invention in front of your eyes

    What is the most important invention of all time? Is it the written word that helps us to record information? Is it the telephone that lets us talk to people from all over the world? Is it the car that lets us travel at great speeds to meet others? Umberto Eco, an Italian writer, thinks it is something quite different. He says the most important invention might be bright in front of your eyes. He is talking about a simple pair glasses.

    Modern eye glasses were invented around 1000years ago. They were more than just a convenient way to read. Before glasses, writers, scientists or teachers who could not see properly had to memorize everything. After about ten years of poor eyesight, they could not remember well enough and could not work. Glasses meant that people could work in their old age.

    People who wanted to remember some information could write it down and read it. Eye glasses are one of the world's greatest inventions and were probably worn by the people who designed the first telephones and cars.

    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 that 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.