Fire can help people in many ways. But it can also be very harmful.

Fire can keep your house 1, give light and cook food. But fire can burn things 2 . Big fire can burn trees, houses, animals and people.

    Nobody knows how people began to use fire.  But there are 3interesting old stories about how a man or a woman started a fire. One is4 a man. The man 5 a very long time ago. He went up to the Sun and 6 fire down.

    Today people know how to make a fire with matches(火柴). Children sometimes 7 to play with them. But matches can be very dangerous. One match can burn a piece of paper, and 8 it can burn a house. A small fire can turn into a big fire very quickly. So you   9 be careful with matches.

    Be careful with fire, and it will 10 you. But if you aren't careful with fire, it may hurt you.

    March 22nd is World Water Day. It started in1993. It not only makes us think about the importance of water, but also calls on(号召）us to1and protect water. Today, we're facing terrible water problems. Among them, wastewater problem is especially 2. And the subject of World Water Day in 2017 is "Wastewater".

    What is wastewater? It is used water. Usually, wastewater comes from homes, 3, hospitals and so on. It is produced by different kinds of activities, including washing the clothes, taking showers and using the kitchen. The rain also4 wastewater when it is running down the street during a storm. No matter where it comes from, this kind of water is sure to have5harmful in it.

    6must we treat（处理）wastewater? Wastewater has a big influence on our life. It causes both illness for us and pollution for the environment. We must care for our environment and our own7.

    How can we treat wastewater? Different kinds of wastewater need different ways of treatment. Wastewater8 homes can be reused. Then there will be9 wastewater. Also, factory wastewater has to be cleaned 10 it goes back to nature.

    Let me tell you something about sharks. Sharks are among the oldest animals in the world. There are over three hundred and fifty different kinds of sharks in the world. Most sharks are about two meters long and live in the oceans.

    A shark can smell something in the water, for example, the blood of animals. That helps them find their food. Sharks mainly eat fish, other sharks and plants in the ocean.

    Most sharks bite (咬)people by mistake. They think a person is a large sea animal. When the sun goes down or comes up, sharks are looking for food. So at these times people shouldn't go swimming in the ocean. Today people kill sharks for food and their skin. The number of sharks in the world is dropping fast.

    Don't be too surprised if you see a car going down the road without a driver in Beijing these days. {#blank#}1{#/blank#}Last month, Baidu began to test its self-driving cars on open roads in Beijing.

    {#blank#}2{#/blank#}Since then, companies like Tesla, Uber and Baidu have been working to produce and test their own self—driving cars.

    Self-driving cars are safer than regular cars. {#blank#}3{#/blank#}They can remove the stress of driving and allow disabled or blind people to get around more easily.

    {#blank#}4{#/blank#}In one test, researchers pointed a laser pointer (激光棒) at the car's sensors (传感器) while it was moving. The car mistakenly thought that the laser beam was in its way and slowed down or changed the direction.

    The software that is used to direct the cars may not be safe enough. {#blank#}5{#/blank#}When we use our computers or smartphones, they sometimes crash (崩溃) without any reason. But if this happened to a self-driving car, the result could be deadly. Improvements to the software could be a solution to this problem.

Do you know about koalas? The koala is 1 Australian animal. It 2 gray and brown fur(皮毛). And the fur on 3 belly(腹部) is white. Koalas eat and sleep in eucalyptus trees(桉树). 4 almost never get down the trees so somebody thinks they are 5 . They are active 6 night and sleep all day. People often think that koalas are friendly animals 7 they look very cute. But they may scratch(乱抓) people if they are not happy. They have sharp claws(利爪). So please 8 friendly to them. In the past, koalas were often hunted(被捕获) because of their beautiful soft fur. Now they are a protected species(被保护的物种) and it's not right 9 them. We need koalas and other animals, because they are our dear 10 !