Bees and other pollinators（传粉者）  use smells to track down fresh flowers. Air pollutants can weaken those scents（气味）.  Scientists had worried this might make it harder for some pollinators to find a meal.

    Many animals help pollinate plants. Species that do this include bees, butterflies, etc. But for many reasons, the pollinators available to help plants in this way are decreasing. Scientists think a loss of habitat（栖息地）can be one factor. Diseases and exposure to poisonous chemicals also count.

    Jose Fuentes points to air pollution as another possible factor. He's an atmospheric scientist at Pennsylvania State University. In an earlier study, he showed some air pollutants could weaken or destroy scents emitted(发出)by flowers.

    Searching for a meal leaves pollinators out in the open and at risk of becoming other animal's lunch. And any time spent hunting food is time away from their duties back home, like protecting a hive（蜂巢）or nest, explains T'ai Roulston. He's an insect biologist at Virginia University. Roulston worked with Fuentes on the new study.

    In the study, the researchers focused on five kinds of representative scent molecules(分子)plants emit. One molecule they looked at, for example, is called beta-myrcene. Many flowers give off this chemical into the air.  Normally, this gas can travel some 800 meters from its flower source. But in polluted air, this same molecule could travel only half as far.

    Worse still, air pollution might do more than just weaken scent plumes（气味烟云）．Chemical reactions between air pollutants and plumes may transform the flowers' smells, creating new scents. And these scents may be unrecognizable to pollinators.

    That's certainly Fuentes' concern.  So, he says his next research project will look at how insects handle any new flower scent. "It's possible that some insects will change ways to detect and use these new molecules to find food," he says.

    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.

    Schools across the world are trying to come up with solutions to keep students active. Some are replacing traditional classroom chairs with exercise balls or standing desks. At Ward Elementary School in Winston, North Carolina students have adopted a new program that requires riding fixed bikes while reading.

    'Read and Ride5 is the creation of school counselor Scott Ertl, who came up with the idea while he was exercising and reading at the gym. Believing it would be a fun way to convince students to become more active, he placed one in the comer of his classroom and encouraged them to use it during independent reading classes.

    It was so popular that Ertl decided to add more bikes and offer the Read and Ride program to the entire school. Today Ward Elementary has a dedicated exercise room filled with bikes that can be used by students while completing their daily reading assignments.

    Besides making reading more fun, the program also helps students exercise at a comfortable pace without the pressure that comes with regular sports-related activities. It is also a perfect way to release energy during days when the weather is not helpful to outdoor activities.

    Most importantly, however, are the program's academic benefits. A year after Read and Ride was introduced at Ward Elementary School, students actively involved in the program demonstrated an astonishing 83% reading proficiency. Those that had not taken advantage of the exercise bikes tested at a much lower, 41%.

    Though the substantial improvement in academic achievement cannot all be attributed to programs like Read and Ride, experts believe they are a significant contributor. That's because studies have shown that physical activity stimulates (刺激) brain cells and helps prepare it for learning. As word of the difference made by this easy to execute exercise program spreads, don't be surprised to find schools across the country adopt “Read and Ride” for their students.

    Zero gravity looks cool. But what about the thing no one likes to talk about? Yes, that is right: going to the bathroom. Zero gravity makes this everyday task quite a challenge. Astronauts have to be toilet-trained all over again.

    The Apollo astronauts raised themselves off the seat of their chairs and stuck a clear plastic bag to their back sides with sticky strips. A second astronaut watched closely to be sure no waste matter escaped the seal. (You would not want that stuff floating around the cabin!) When the deed was done, the astronaut cleaned up with a piece of plastic attached to the inside of the bag, removed the bag, dropped a disinfectant(消毒剂) pill in with the waste matter, and put the whole thing, sealed, into a special container.

    Donald W. Rethke, an engineer for Hamilton Standard Space Systems, developed a more private way to answer nature's call: the space toilet. It is somewhat like the kind of toilet one would find on commercial airplanes--with unique adaptations for zero gravity, of course. For instance, it has thigh bars that keep the astronaut from floating off the seat.

    The astronaut (male or female) defecates (排便) in a bag and urinates (排尿) in a hose. Solid and liquid wastes are kept separated because at least 85% of the urine is recycled and, yes, after careful filtration(过滤), used for drinking and other purposes. (Water is always in demand in space.) A vacuum sucks the waste materials into the toilet, where the waste is compacted into hamburger-like patties for easy storage. Although not exactly like an earthbound visit to the toilet, it is at the very least much more private than in the early days of space travel.

    Raccoons are smaller relatives of bears. They are native to North America, but they can also be found in Asia and Europe. Raccoons live in wooded areas close to water, but they can be often found near urban areas. There are about 7 different species of raccoons. Pygmy raccoon is the only endangered species.

    Raccoons usually reach 40 to 70cm in length and weigh between 5­26kg. Raccoons that live in colder climates are larger and heavier. They have grayish fur, black masks around eyes and long tails covered with black and brown bands. Because of their tails, they are also called "ringtail".

    Raccoons are omnivores. They like to eat insects, eggs, small mammals, fruit, berries, garbage, and so on. Raccoon's hands look like human's. They each have five fingers and are used to collect food, open shells, door or trash cans. Raccoons often place food in water before they start to eat it. They have highly sensitive sense of touch and water increases their sensitivity even more. By touching the food, they get better insight about things they will eat.

    They are easily adaptable (适应的) to various environments. They can live in hollow (中空的) trees equally happily like they can in useless cars. Raccoons live on their own and hunt at night. They don't hibernate (冬眠), but they spend the coldest days of winters in their holes.

    Mating (交配) season takes place from January to mid March. Two months later, female will give birth to 3­4 babies. Their tails don't have bands, and the mask around eyes is still missing. Mother is very protective and she will teach them how to survive and what to eat as they become­ready to leave the hole. Raccoons usually can live only 1.8 to 3.1 years in the wild, but they can live up to 20 years at a zoo.

    Raccoons can pass rabies, a kind of disease, to home­raised animals and people, which is very dangerous. What's more, their waste often has roundworms.

    On a rainy winter day, several decades ago, a British artist named Christopher got on a train in Oxford to go to London. When he began his journey, he never knew that it was the beginning of almost 40 years of accidents and near death experiences.

    During the journey, the train fell into an icy river, killing 12 passengers. Christopher managed to swim back to the river bank. He only had a broken leg.

    Two years later, Christopher was on a plane from London to Manchester when a door suddenly opened and he fell out. A few minutes later, the plane crashed; 27 people were killed. Christopher was so lucky that he landed in a haystack (干草堆).

    A few years later, he was hit by a bus, but again had no serious injuries. Then a year after that, he was driving on a mountain road when he saw a truck coming straight at him. He drove the car off the road, jumped out, landed in a tree — and watched his car fall 100 meters down the mountain.

    "There are two ways you can look at it," Christopher said. "I'm either the worlds unluckiest man, or the world's luckiest." When a reporter asked Christopher what he thought, he chose the "luckiest" one.

    Two years ago, aged 71, Christopher bought his first lottery ticket (彩票) in 50 years and won more than 2 million. After this, a TV company in America said they wanted him to make an advertisement. At first he accepted, but then he changed his mind. Christopher said he would not fly to Los Angeles for the filming, because he did not want to push his luck. Who knows? If he had accepted the invitation, maybe he would have had another accident. But Mr. Christopher is a lucky man. If he had had another accident, he probably would have survived that too!