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    Do you and your friends ever talk about your dreams with each other? If you do, you might have noticed something interesting – some of your friends seldom remember their dreams, but some can always describe their dreams so clearly that it seems like they're describing things that really happened to them. What makes those people different?

    The answer is simple. There are two different types of dreamers – low dream recallers（回忆者）and high dream recallers.

    Low dream recallers usually remember their dreams only twice a month. But high dream recallers are able to remember them about five mornings a week. And a new study suggests that activity in a certain part of the brain could have something to do with it, reported The Huffington Post.

    Perrine Ruby, a French researcher at the Lyon Neuroscience Research Center, studied 41 people (21 high dream recallers and 20 low dream recallers) and recorded their brain activity.

    She found that a part of the brain called the temporo-parietal junction (颞顶联合区) was more active in high dream recallers than in low dream recallers – both when they were sleeping and awake.

    This brain area collects and processes（编程）information from the outside world. This means that high dream recallers know more about what's happening around them. For example, when they are awake, they respond (对……有反应) more strongly to hearing their own names, and when they are sleeping, they are woken more easily by sounds and movements.

    By closely studying people's brain activities, Ruby found that high dream recallers have twice as much “wakefulness time” during sleep as low dream recallers do. And it is during these short times of wakefulness that the brain remembers dreams.

    “The sleeping brain is not able to remember new information,” Ruby told The Washington Post. “It needs to wake up to be able to do that.”

    This is not hard to understand. Just try to think of your own sleeping experiences. If you are worried during the night, you are more likely to remember your dreams, but if you sleep well, you will remember little in the morning, and this is because “you never get a chance to remember”, Robert Stickgold, a Harvard Medical School researcher, told The Washington Post.

    Scientists have been experimenting with four-leg robots for years. They want to use robots to carry heavy things over difficult land.

    But providing enough power for those kinds of robots has been a problem. Now, that has changed. Engineers at MIT have designed a running robot that runs on batteries. Scientists say their robots will soon be able to run like cheetahs, the fastest land animals on Earth.

    One difficulty in designing these types of robots continues to be providing power. These machines are still quite heavy and they need a lot of power to run. But the cheetah-like robot designed by engineers at MIT is light enough m run on batteries. The robot weighs just 30 kilograms. The robot needs only about 700 watts of power to run. This robot can actually jump 40cm high and it can land very safely and then it can run. The robots limbs and other parts were made in a three-dimensional or 3D printer. A strong, light-weight material called Kevlar is used to make the robot's part stronger.

    But the development of MITs robot is not without its own set of problems. The robot's limbs must support heavy force, and sometimes they break.

    Scientists say the new technologies used on this robot may be used in the making of limbs for disabled persons and other machines. Some of those machines may help save humans from performing difficult and dangerous jobs.

    The polar bear is a very big white bear. We call it the polar bear because it lives in the Arctic Circle（北极圈） near the North Pole.

    The polar bear lives in snow and ice. At the North Pole there is only snow, ice and water. There is not any land. The polar bear has a very warm coat because the weather is cold in Arctic Circle. You can't find the polar bear easily in the snow because its coat is white.

    A grown-up polar bear is usually about three meters long and weights about 450 kilos. It can stand up on its back legs because it has very wide feet. It can use its front legs like arms. The polar bear can swim very well. It catches fish and sea animals for food. It goes into the sea when it is afraid. People kill the polar bear for its beautiful white coat. The governments of Canada and United States call on that people should stop killing polar bears. They don't want these beautiful animals to die out.

根据短文内容回答问题。

    North American black bears are shy animals. They are fearful by nature, and will usually run away if they see or hear people. Because of this, it can be difficult for scientists to learn about these animals.

    In order to study black bears, researchers from New Jersey, the US, catch bears and use drugs to help them go to sleep. Researchers then work out the size and the weight of the bears, take blood, to test for diseases, remove a tooth and take it to the lab to find out its age. From these studies, researchers want to find out how many bears live in New Jersey, how long they live, and how many babies they produce.

    But in Minnesota, the US, researchers study bears that are completely awake. The bears know the researchers' voices and they are not afraid of the research team. With the help of a few grapes to keep the bears busy, researchers can touch them to check their hearts, look at their teeth, and do other jobs. Researchers can also walk or sit with bears for hours and make videos to learn about their everyday lives."

    In both places, the main purpose is the same—to make sure there is a healthy population of black bears. But the research methods and the kinds of information that researchers are able to collect are quite different.

    Give your dead batteries a new life. Recycle them！

    Batteries(电池) are used to power clocks, computers, tools and more. However,

Your batteries have some serious power when their lives are over.

WHY TO RECYCLE BATTERIES

    Remember, batteries are harmful waste. This mean you could properly throw away. You may not think one little battery can cause that much pollution. But don't think of it as just one battery—there can be millions. In Canada, each person uses about 20 single-use batteries every year. That's about 700 million batteries! If all these batteries end up in landfills(垃圾填埋场), the heavy metals inside them can get into the water, land and air. It can be harmful to humans and wildlife.

    By recycling single-use batteries instead of throwing them away, you can cut down pollution and also help save energy. All batteries are mainly made of plastic and valuable metals. Through recycling programs, dead batteries can be changed into something useful like steel products, or even new batteries!

    HOW TO RECYCLE BATTERIES:

    Make a difference by starting to collect batteries at your home or school today. You can prepare a box for battery collection and invite friends, family and classmates to bring in old batteries to be recycled.

    There are many safe ways to deal with your batteries. You can:

    Find a Call 2 Recycle public collection station near you.

    Ask the store where you bought the batteries if you can return them there.

    Communicate with your local city government to find out if there are special programs for recycling used batteries!

    For more information, visit https://ecokids.ca/batteries.

    We all want to protect the environment, but we're mostly too busy or too lazy to put up big change. There is nothing new here but if you follow at least some of these tips, you can be proud of yourself in the protection of the environment.

    Use LED light bulbs: They last much longer and they can save energy.

    Donate: You have many clothes or things you want to throw. If they are still usable, give them to someone who needs them.

    Turn off your devices: When you do not use a house device, turn it off. For example, if you don't watch TV, turn it off. Turn off the light when you leave a room.

    Walk or cycle: Driving is one of the biggest causes of pollution. If you want to use your car, ask yourself the following question: do I really need my car? Walk or use your bike if the journey is a short one.

    Detergent (洗漆剂):Use less dose of detergent to wash your clothes or dishes.

    Leaky faucets(漏水龙头):Fix them, or they will waste a lot of water.

    Rainwater: Think of collecting rainwater. This water can be used for different purposes.

    All these tips will help you save money and protect the environment.