The population of the Earth is growing faster. It is important that we look after the Earth. We need it! The Earth gives us a lot of things. We also give the Earth a lot, but some of the things are not good.

   In nature, when something dies, other animals and plants get food from it. Every animal or plant gives food for other animals or plants. However, animals can't get food from many of the things that we "give" the Earth. Animals and plants can't eat metal, plastic and glass. These things will stay in the ground for many, many years.

   Some rubbish is very dangerous for plants and animals. In some places, many animals live together. One animal makes food for many more animals. If we put rubbish and chemicals in the water, the plankton(浮游生物) can die. If there isn't any plankton, many animals have nothing to eat.
   So what can we do? Don't leave any rubbish in the countryside! Don't make so much rubbish!

   The ocean can be a great place to swim and play, it may also be useful in another way. Some scientists think that waves could help make electricity.
   “Have you ever been on a surfboard or boat and felt yourself being lifted up by a wave?” asked Jamie Taylor of the Wave Energy Group in Scotland. “There is certainly a lot of energy in waves.”
   Scientists are working on using that energy to make electricity. The United States and a few other countries have started doing research on wave energy, and it is already being used in Scotland.
   Most waves are created when winds blow across the ocean. “The winds start out by making little ripples (波纹) in the water, but if they keep on blowing, those ripples get bigger and bigger and turn into waves,” Taylor said. “Waves are one of nature's ways of picking up energy and then sending it off on a journey.”
   When waves come towards the coast, people can set up dams(大坝) to block the water and send it through a large wheel called a turbine(涡轮). The turbine can then power an electrical generator(发电机).
   We will never run out of wave power. Besides, wave energy does not create the same pollution as oil and coal do.
   Oceans cover three quarters of the earth's surface. That would make wave power seem perfect for creating energy around the world. But there are some disadvantages that need us to pay more attention to.
   Jamie Taylor said that wave power still cost too much money. He said that its influence on animals in the sea is still unknown. Besides, wave power would get in the way of fishing and boat traffic.
   With more research, “Many of these problems might be solved,” Taylor said. “Finding more energy sources(资源) is very important, for traditional sources of energy like oil and gas may run out some day.”
   In the future, when you turn on a light button, an ocean wave could be providing the electricity!

    Compared with other European countries, lifestyle in Italy is slower and more relaxing in its own way. Italians love to chat over a cup of coffee, go out for a walk in the middle of the day, and enjoy long lunches and dinners.

    The family is important to Italians. They can't think of spending a day without talking about their parents and children, or a weekend without a family lunch or dinner. Italians living outside their country miss their family a lot.

    Italians like simple life. Their days start and end with a cup of coffee. A cup of coffee after every meal is a must. Italians love to spend time over a hot cup of coffee and even hotter conversation with friends. Topics are usually about family, football and politics(政治).

    Sport is a very important part in lives of many Italians. Football is their favorite sport. There are hundreds of football clubs with top football teams in Italy. Also, many top players from all over the world play in Italy. Volleyball is also popular and so is rugby, with the top rugby team playing for the European Challenge Cup.

Every Italian province, city, town and street has a historical event that took place there and the Italian calendar is filled with national holidays that they love to celebrate.

    Most people agree that trees look nice, but not everyone knows that trees can also help cities save money. A few years ago, the US Forest Service studied trees in Chicago. They found that just one tree can save a city hundreds of dollars over its lifetime.

    Trees can save money by helping people save energy(能源). Trees stop the sun shining on buildings. They also block(挡住) the winter wind. That helps people use less energy to make their homes or offices warm or cool. Saving energy is saving money.

    Trees have another way to help a city save money. When it rains, there will be a lot of water in a city's sewers (下水道). Cities need lots of money to clean that water. But before the rainwater gets to the dirty sewers, trees can take some into themselves. With the help of trees, there is less water to clean.

    A thirsty crow(乌鸦) comes across(偶然遇到) a bottle of water, but the water level is out of its reach. The bird then drops some stones into it and gets the water.

    "It's just a story," you may think. But new research has found that crows' brains may sometimes be better than those of 6­year­old children.

In a recent experiment, American scientist Corina Logan and her team caught six crows to test them. The crows and children had to choose between two sets of tubes(试管). They had to drop stones in and get water.

    With the red set, when they dropped a stone into a wide tube, the water level raised in a connected narrow tube. The blue set of tubes, however, had no connection between them.

    Children aged 7 to 10 were able to learn the rule. Children aged 4 to 6, however, failed. Five of the six crows failed the test. But Kitty, a 6­month­old crow, passed it. She put most of the stones into the red tubes.

    So, could a bird be more clever than a kindergartner? Don't be too quick to say no.