It is said that if you want to stay young, sit down and have a good think. This is the research finding of a team of Japanese doctors, who say that most of our brains are not getting enough exercise — and as a result, we are growing old unnecessarily soon.

    Professor Taiju Matsuzawa wanted to find out why otherwise healthy farmers in northern Japan appeared to be losing their ability to think and reason at a relatively early age, and how the process of aging could be slowed down. With a team of colleagues at Tokyo National University, he set about measuring brain volumes of a thousand people of different ages and varying occupations. Computer technology enabled the researchers to obtain precise measurements of the volume of the front and side parts of the brain, which controls functions like eating and breathing, does not contract with age, and one can continue living without intellectual on economical faculties. Contraction of front and side parts — as cells die off — was observed in some subjects in their thirties, but it was still not evident in some sixty-and seventy-year-olds. Matsuzawa concluded from his tests that there is a simple way to the contraction normally connected with age — using the head.

    The findings show in general terms that contraction of the brain begins sooner in people in the country than in the town. Those least at risk, says Matsuzawa, are lawyers, followed by university professors and doctors. White collar workers doing routine work in government offices are, however, as likely to have shrinking (萎缩) brains as the farm worker, bus driver and shop assistant.

    Matsuzawa's findings show that thinking can prevent the brain from shrinking. Blood must circulate properly in the head to supply the fresh oxygen the brain cells need. “The best way to maintain, good blood circulation is through using the brain.” he says. “Think hard and engage in conversation. Don't rely on pocket calculators.”

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    The four best films in China in the first quarter of 2018

    Quite a few films both at home and abroad have brought a wave of heated discussions on the Internet in the first three months of 2018.

    If you're looking for some good films to see, here are some recommendations. While the subjects of these films are different，they all have fascinating storylines, a star-studded cast and thought-provoking themes. Let's take a look at them.

    Wonder

    Country: United States

    Release Date: Jan 19, 2018

    Genre: drama

    Starring: Julia Roberts, Owen Wilson, and Jacob Tremblay

    Director: Stephen Chbosky

    Recommendation Index: ★★★★★

    On the theme of “We all are different and want to be treated with kindness,” the film earns its tugs at the heartstrings. The movie was praised by audiences for hitting the soft spot as a heartwarming story that manages to avoid turning too sentimental.

    Forever Young

    Country: China

    Release Date: Jan 12, 2018

    Genre: drama

    Starring: Zhang Ziyi, Huang Xiaoming, Wang Leehom

    Director: Li Fangfang

    Recommendation Index: ★★★★

    The film, once planned as a tribute to mark the centenary celebrations of Tsinghua University in 2011, weaves four stories set in different eras to look at the history of the college.

    Secret Superstar

    Country: India

    Release Date: Feb 16, 2018

    Genre: musical drama

    Starring: Zaira Wasim, Aamir Khan

    Director: Advait Chandan

    Recommendation Index: ★★★★

    The film deals with social issues including feminism, gender equality and domestic violence. From Dangal to Secret Superstar to the latest comedy-drama film Bajrangi Bhaijaan, Indian films have developed a solid fan base in China.

    The Ex-File: The Return of the Exes

    Country: China

    Release Date: Dec 29, 2017

    Genre: romantic comedy

    Starring: Han Geng, Zheng Kai

    Director: Tian Yusheng

    Recommendation Index: ★★★

    The Ex-File: The Return of the Exes, the finale of the hit romance franchise produced by Huayi Brothers and New Saint Film Studio, revolves around bittersweet stories of two young businessmen who break up with their girlfriends. It is the first movie in 2018 that has achieved huge success at the box office.

    If life is a beach, then a village in Ireland has come back from the dead after the sand returned 33 years later due to a freak tide.

    Dooagh beach on Achill Island in the west of Ireland, was washed away in 1984 after storms hit the area, leaving a rocky foreshore. The tourists left, causing the hotels and guesthouses as well as the cafes to close down. But in April this year, the sand returned over a ten-day period caused by an unusually high tide that deposited hundreds of thousands of tons of sand along the 300m beach, bringing the beautiful beach back to its former glory.

    Emmet Callaghan from Achill Island Tourist Office told the journalist that the people of the island were excited at the beach's reappearing. “It's so nice for the villagers to have their beach back. It is an incredible example of the force and power of nature and how the coast can change in a matter of days. Yesterday we had traffic block here in the village with cars and people coming from all over Ireland and the UK to see our new beach,” he said. “The people here have always spoken about their days on the beach and how they enjoyed it as children. To have it back with their kids is unbelievable. Now locals are hoping that the beach is given the blue flag status. We already have five blue flag beaches and hopefully, if we keep our beach here, we'll have a sixth.”

    Dr Ivan Haigh from the University of Southampton said there were two explanations as to why the beach has reformed. “It could be a change in sediment (沉积物) supply, from further up or down the coast which has brought a fresh amount of sediment to the beach,” he said. “It could also be due to a change in environmental conditions, either a change in the wave climate or a series of tides that have provided the ideal conditions for this beach to reform.”

    The tourism office and locals hope the new beach will stay, at least for the summer of this year.

    After decades of playing catch-up with the U.S. and Russian space programs, China did something neither nation nor any other had done this December: land a spaceship on the dark side of the moon.

    Strictly speaking, of course, the moon has no dark side. But because of the way it orbits Earth, our natural satellite shows us only one side－the other is hidden from our view. No one even saw the far side until 1959, when the Soviet Luna 3 spaceship flew around for a look and sent back photos. No astronaut or spaceship went there until this December, when the China National Space Agency (CNSA) launched a 2,500-pound lander called Chang'e-4 to the southern end of the lunar far side.

    Chang'e-4 operated a small rover (探测车) to survey the geography there for the first time ever. By examining the geography of its landing area, Chang'e-4 could solve longstanding puzzles about the moon, including how it formed 4.5 billion years ago. Chang'e-4 also carried a very small lunar biosphere (生态圈) containing silkworm eggs and a tiny greenhouse designed to grow potatoes in order to study the growth of the seeds on the moon.

    Besides Chang'e-4, China plans to launch Chang'e-5 in 2019. Its mission will be to gather moon rocks using an orbiter, a lander or collector, an ascent stage (上升器) and a capsule that will separate from the orbiter and return the rocks to the earth. ―With these missions, the Chinese will have shown complete mastery of flight in the space between the earth and the moon, said Paul Spudis, an experienced lunar researcher based in Houston.

    CNSA has already outlined ideas for Chinese astronauts to follow the robots to the moon. Pei Zhaoyu, deputy director of CNSA's Lunar Exploration and Space Program Center, told that China plans a permanent robotic lunar station in about 10 years and suggested a human presence on the moon another decade or so after that. Spudis said China's ambitious Chang'e-4 and Chang'e-5 missions should send human's plans for lunar return into rapid development.

    Hotshot jet pilots are no match for cliff swallows. The birds rocket over bridges and skim over lakes, rushing forward at accelerations that would knock an Air Force. By tracking these contests with high-speed cameras, a new study gives the first, in-depth peek into avian aerodynamics (鸟类空气力学) in the wild. "The findings may even provide insight into how to design better micro air vehicles-tiny drones. This technology will be brilliantly useful," says biomechanics expert Jim Usherwood of the United Kingdom's Royal Veterinary College in Hatfield. "High-resolution field studies like this have never been done before for birds."

    For cliff swallows, the trouble starts when they return from wintering in South America to their summer homes in North America. After arrival, they seek out their old mud nests—usually located under concrete bridges and freeways-and start rebuilding their homes. But rather than hunt down a fresh supply of mud, some swallows prefer stealing supplies from their more hardworking neighbors. Others take things further and will even lay an egg or two in their neighbor's nest before taking off.

    Battles in the air follow if the invaders are caught in the act, and a new study takes advantage of these fights to learn how birds perform high-speed maneuvers (演习). The team placed three cameras along a North Carolina lake crossed by a highway bridge that houses several cliff swallow nests and waited for the battles to commence.

The team was surprised to learn that most of the time, chasers copied the move of fleeing invaders. Swallows also pull very hard turns to escape an enemy, with one extreme case reaching 7.8 gravity. Fighter pilots usually pass out at about 5 or 6 gravity, which is why these experiments have earned interest, and partial funding, from the Office of Naval Research. The Navy may use the findings to build better guidance systems for micro air vehicles. However, the swallows' biomechanics are complex, and now the team is simply trying to collect a few tricks.

    My sister Alice and I have been trying to get people to stop dropping cigarette (香烟)butts(烟头)for seven years. One day, we were walking in our hometown and saw hundreds of cigarette butts on the ground. They made the town look so ugly that we decided to start a group to make people dropping butts. We called it "No Butts About It".

    At first, we drew pictures with "The Earth is not your ashtray(烟灰缸)"written on them. We put the pictures around our hometown—in parks, by beaches, and along roads. We wanted to make people understand that dropping butts hurts the environment. Most smokers don't think that dropping butts hurts the Earth. But it does, and all rubbish does!

    Later, we wrote to companies and asked them for money to help us. We used the money to buy ashtrays to give to smokers. We wanted smokers to carry the ashtrays with them so they didn't have to drop butts.

    At the moment, we are trying to get cigarette companies to put an ashtray in each pack of cigarettes. Some companies want to do it. Many people have started to join our group since it began. Today there are 45 other "No Butts About It" groups in America.

    Now there even groups in England, Australia, and India! Many newspapers have written about my sister and me over the last seven years. And we have won many prizes for what we do. But we are not interested in prizes. We just want to make the Earth a better and cleaner place for animals, plants and people.

    One day, it will be.