Why do plants grow in some places and not in others? Why does some land have so many plants growing on it, while other land has almost no plants growing on at all?

    To grow, plants need some things. One is warmth. In very cold places, almost nothing grows, Plants also need water. In very dry parts of the Earth, only a few unusual plants can grow. That's why dry deserts(沙漠）almost don't have trees or grass.

    Plants must also have a place in which to put down their roots（根）and grow. They find it difficult to grow on hard land. The town is on hard land. The plants here can only grow in the soil（土壤）between the cracks of the stones.

    Another thing plants must have before they can grow is food.

    What will happen if we try to make things grow on the sandy（有沙的）beach? A few plants, such as beach grass, will grow in sand, but most plants won't. Even if（即使）the weather is warm enough and we water the plants each day, many of them will die because the sand on this beach has almost no food for plants.

     With the development of the Internet, many people use it very often, including some teenagers. But many parents are worried about that their children may meet with something unhealthy online. To solve this problem, a new search engine for children named Kiddle has appeared.

     Search results are filtered, so only safe website are shown and descriptions are written in simple language. Searches with bad words are shut off, too. Kiddles uses the same color as Google in its logo and a similar design on its homepage, too— with an extra robot picture. The top three Kiddle research show safe websites and pages written specially for kids and those websites and pages are well chosen and checked by Kiddle developers. The fourth to seventh results will be safe and trusted websites that are not written for adults. They provide expert content, but are harder for kids to understand.

     Unlike on Google, most results appear along with large thumbnail pictures(缩略图) to make it easier for children to find what they are looking for. For example, when you search for “meow meow”. Google produces pages for information about a drug(毒品)，but Kiddle lists information only about cats. The company explained, “Websites which appear in Kiddle search results satisfy family–friendly requirements, as we filter websites with unhealthy content.”

    Sheridan is a town in Indiana, USA. There are lots of trees near the public schools in the town. Their leaves turn sunlight into energy.

    In Sheridan, the Sun not just provides energy for plants. It keeps schools running, too. The schools use solar panels(太阳能电池板) to turn sunlight into energy.

    The science behind solar energy is not new. But Sheridan Community Schools is the first school district (学区) in Indiana to be completely solar-powered. The district finished putting in solar panels for all three of its schools in 2016. Some of the panels can turn to follow the Sun across the sky.

    In 2008, fewer than 1,000 schools used solar power. By 2014, there were 3,727 schools with solar panels in the USA. These numbers come from a report by The Solar Foundation. Roxie Brown, a programme director there, said that the number of schools with solar panels has continued to go up since 2014.

    Solar energy has some advantages over other energy sources (来源). Sunlight is a renewable source, which means it won't run out. Solar panels don't harm the environment. Also, sunlight is free. So by using solar power, schools can save money on energy costs. Brown thinks more schools should run on solar energy. "The Sun is Earth's energy source," she says. "We're trying to make it the energy source for our houses, cars and schools, too."

    But using solar energy isn't always easy. Solar panels can be expensive to put in. The panels also take up space. But for many schools, going solar is worth it.

    Pisces is the twelfth star sign. There is a legend about its name.

    Long, long ago, there was a war between gods and a bad monster (怪物). It lasted ten years. One day, the gods were surprised to find that the monster was coming towards them. The goat god Pan shouted a warning and tried to change himself into a fish. One god, Aphrodite, took her little boy Eros and tried to hide among the bushes near Euphrates River. She was the god of love and her son was the god of war. It is said that two fish swam to carry Aphrodite and her child to safety. Some people also believe that Aphrodite and Eros changed into fish themselves and swam away to safety. Later the fish represent Aphrodite and her son Eros.

    As they appeared in the sky, the two fish were tied together by a rope (绳子). Some said that Aphrodite tied the little boy to her body so that he would not get lost as they swam away to safety. That's the story about Pisces.

    In Western countries, some people believe people will share similar characteristics if they have the same star sign. So if you're born between February 19th and March 20th, your star sign is Pisces. It means that you are generous, easy-going and creative.