A strong memory depends on the health and vitality （活力） of your brain. They say that you can't teach an old dog new tricks, but when it comes to the brain, scientists have discovered that this old saying simply isn't true. {#blank#}1{#/blank#}

      Give your brain a workout. Memory, like muscular strength, requires you to “use it or lose it”. The more you work out your brain, the better you'll be able to process and remember information.{#blank#}2{#/blank#}

        Don't skip the physical exercise. While mental exercise is important forbrain health, that doesn't mean you never need to break a sweat. Physical exercise helps your brainstay sharp. It increases oxygen to your brain and reduces the risk for disorders that lead to memory loss.

        Get enough sleep. There is a big difference between the amount of sleep you can get by on and the amount you need to function at your best.{#blank#}3{#/blank#}Keep stress in check. Stress is one of the brain's worst enemies. Over time, stress destroys braincells. Studies have also linked stress to memory loss.

        Have a laugh.{#blank#}4{#/blank#} That holds true for the brain and the memory, as well as the body. Unlike emotional responses, which are limited to specificareas of the brain, laughter engages multiple regions across the whole brain.

{#blank#}5{#/blank#}Just as the body needs fuel, so does the brain. You probably already know that a diet based on fruits, vegetables, whole grains, “healthy”fats and lean protein will provide lots of health benefits, but such a diet can also improve memory. For brain health, though, it's not just what you eat—it's also what you don't eat.

A. Eat a brain-boosting diet.

B. Play games with memory.

C. Laughter is the best medicine.

D. But oversleeping is not good for yourbrain.

E. Even skipping a few hours makes adifference!

F. You have to shake things up from timeto time!

G. The human brain has an astonishingability to adapt and change.

    On October 31st, 2009, Chinese famous scientist Qian Xuesen, died in Beijing when he was 98 years old. He is famous as “the country's father of space technology and king of rocketry”.

    Qian was born in 1911 in Hangzhou. He left for the United States after winning a scholarship to graduate school in 1936. He studied at the Massachusetts Institute of Technology and later at the California Institute of Technology.

    Qian began his career in the US and was regarded as one of the brightest minds in the new field of aeronautics（航空学) before returning to China in 1955.

    After he returned, Qian set up the first missile（导弹）and rocket research institute（学院) of China. The institute later helped start Chinese space program. He led the development of China's first nuclear-armed ballistic missile (弹道导弹) and worked on its first satellite.

    He retired in the year before Chinese manned space program was launched in 1992. But his research formed the basis（形成基础）for the Long March CZ -2F rocket that carried astronaut Yang Liwei into orbit in 2003.

    In August, 2009, Chinese Premier Wen Jiabao visited Qian and praised him for devoting his life to Chinese defense technologies. Qian told him, “I'm trying to live to be 100 years old”.

    Most nations have at least one type of food that people from other countries think is unusual or unethical（不道德的）to eat. In France, people eat horse meat and frog legs. In South Korea and parts of China, restaurants serve dog meat. And in Australia, it's common to cook kangaroo meat on the barbecue and use emu（鸸鹋）eggs to make pancakes.

    The kangaroo and emu are native to Australia. Both animals are important to the national image of Australia and appear on the Australian coat of arms. They're also central figures in the history of the indigenous（土生土长的）Australian Aboriginals（土著人）. However, Aboriginal tribes still hunt these animals for their meat, fur and fat.

    Today, Australian people continue to eat these animals. One of the reasons people eat kangaroo meat is that it's high in protein and low in fat, so eating kangaroo is a good option for anyone on a diet. It's also cheaper to eat kangaroo meat than other red meats. Because of this, a lot of university students choose to buy kangaroo meat. BBC News also reported that Australian scientists believe that eating kangaroo meat is good for the environment--kangaroos have different digestive systems than cows and sheep, meaning they produce less methane（甲烷），the second biggest contributor to global warming.

    While emu meat is high in iron and vitamin C, most people don't think it tastes good. For this reason, they prefer emu eggs. One egg is large enough to make seven omelettes（煎蛋）. And while it's illegal to collect emu eggs from the wild, they can be bought from emu farms. Rather than cracking the beautiful dark shell, it's better to drain it by putting a small hole at each end and blowing. Afterwards, you can even carve a design into the eggshell.

    Even if trees cannot walk, they are still on the move.

    In parts of the Arctic, entire forests are moving northward. Across the Arctic, temperatures are rising faster than anywhere else in the world. As that happens, the tree line that marks where forests stop and the treeless tundra(冻土地带) starts has been shifting northward. Trees growing along the tree line must protect themselves from the cold wind. To do this, plants tend to grow horizontal(水平的) branches low to the ground. The energy it takes for trees to grow this way means they don't have enough energy to make seeds.

    But as Earth's climate has been warming, trees no longer have to just grow horizontally. Many can instead grow up toward the sky. This takes less energy. And with all the leftover energy. these trees have started producing more seeds. This happens especially in places where the white spruce(白云杉) grows.

    White spruce, which is a North American tree, is quite able to produce a lot of seeds, which can move long distances in the wind. When wind-blown seeds end up on the tundra beyond the tree line, they eventually can sprout(发芽) new trees. This explains how a forest can move. Of course, the process would work only if the tundra were warm enough. But in recent years, the whole planet has been warming.

    New trees will provide shelters for some snow, keeping the sun's rays from making the white surface disappear. Instead, the trees absorb the sun's heat. This warms the surrounding air. The extra warmth encourages even more trees to produce seeds. That further boosts a forest's ability to expand. In addition, more trees will trap more snow, preventing much of it from being blown away. Snow can trap heat in the soil below, which encourages trees to grow. The recent rise of temperature has helped more trees grow. The recent rise of temperatures has helped more trees grow past the tree line. People worry about impacts on the animals that depend on frozen conditions for food and shelter.

    Whether in the home or the workplace, social robots are going to become more common in the next few years. Social robots are about to bring technology to the everyday world in a more humanized way, said Cynthia Breazeal, chief scientist at the robot company Jibo.

    While household robots today do the normal housework, social robots will be much more like partners than tools. For example, these robots will be able to tell when someone is happy or sad. This allows them to respond more properly to the user.

    The Jibo robot, arranged to ship later this year, is designed to be a personalized assistant. You can talk to the robot, ask it questions, and make requests for it to perform different tasks. The robot doesn't just give general answers to questions; it responds based on what it learns about each person in the household. It can do things such as reminding an elderly family member to take medicine or taking family photos.

    Social robots are not just finding their way into the home. They have potential(潜在的) applications in everything from education to health care and are already finding their way into some of these areas.

    Fellow Robots is one company bringing social robots to the market. The company's “Oshbot” robot is built to assist customers in a store, which can help the customers find items and help guide them to the product's location in the store. It can also speak different languages and make recommendations for different items based on what the customer is shopping for.

    The more interaction the robot has with humans, the more it learns. But Oshbot, like other social robots, is not aimed to replace workers, but to work together with other employees. “We have technologies to train social robots to do things not for us, but with us,” said Breazeal.

    The vast majority of green sea turtles in the northern Great Barrier Reef are female because of warmer temperatures due to climate change, which influences their sex, researchers said. Scientists are concerned populations of these animals could turn almost completely female.

    A recent study by the National Oceanic and Atmospheric Administration, California State University and Worldwide Fund for Nature Australia examined two genetically distinct populations of green sea turtles living in the Great Barrier Reef. The study found that a group of about 200,000 turtles living in the northern part of the reef was almost entirely female. While the southern population was 65 to 69 percent female, females in the northern group accounted for 99.1 percent of young turtles and 86.8 percent of adults.

    After combining their results with temperature data, the scientists found that most sea turtle populations are living above the most suitable temperature. The northern green turtles have been producing mainly females for more than two decades and that the complete feminization of this population is possible in the near future, making it clear that climate change is threatening the survival of these populations.

    Dermot O'Gorman, the chief executive of World Wildlife Fund Australia, said, “That's a very visible sign of the impact of climate change. But this is a quiet change.”

    O'Gorman said more urgent action on climate change is clearly needed, adding that some conservationists have already taken practical measures, such as using shade cloth on turtle nesting beaches to lower the sand temperature, and reducing by catch in the fishing industry.

    “Shade cloth can be used in certain places, but there's a limit to the scale you can do that,” he said, “Now every large male who can reproduce is going to be even more important.”