阅读下列短文：从每题所给的 A、B、C、D 四个选项中，选出最佳选项，将正确的选项涂在答题卡上。

Is there link between humans and climate change or not? This question was first studied in the early 1900s. Since then,many scientists have thought that our actions do make a difference. In 1997,the Kyoto Protocol explained our role in the Earth's changing atmosphere and set international limits for gas emissions(排放) from 2008to 2012. Some countries have decided to continue these reductions until 2020. More recently, the Paris Agreement, stuck by nearly 200 countries, also aims tolimit global warming. But just now how much warmer it will get depends on how deeply countries cut carbon emissions.

    Food storing is common in members of the crow（乌鸦）family. A new study tested the birds outside this naturally occurring behaviour, which may have evolved（进化）specifically because it gives crows a survival advantage. Some crow species are known to naturally use tools to recover food. So the researchers tested whether the birds could store and recover a tool so they could get it at their food after a gap of 17 hours—something we wouldn't expect them to do naturally. But they were able to instantly select the tool out of a number of unnecessary items.

    In another experiment, the researchers taught crows to select a token （礼品券）from a number of items so that they could then exchange for food. Again, the birds then showed that they could plan for the future using this new behaviour. This is different from all of the previous studies in future planning, which have focused on naturally occurring behaviour. For example, we know that chimpanzees select, transport and save appropriate tools for future needs.

    These studies have shown that animals can plan for the future—but they left an important question open for debate. Are animals only able to plan to use abilities that have evolved to give them a specific advantage, or can they flexibly and intelligently apply planning behaviour across various actions? Most critics would say the former, as the animals were tested in naturally occurring behaviours.

    But the new research provides the first evidence that animal species can plan for the future using behaviour that doesn't typically occur in nature. This supports the view that at least some recognitive abilities in animals don't evolve just in response to specific problems. Instead, it suggests that animals can apply these behaviours flexibly across problems in a similar way to humans. We need to investigate how flexible behaviour evolved. Then we might be able to see how crows' ability to plan for the future fits in with their broader cognitive powers.

    First, I want to tell you how proud we are. Getting into Columbia shows what a great well-rounded student you are. Your academic, artistic, and social skills have truly blossomed（开花）in the last few years. You have become a talented and accomplished young woman. You should be as proud of yourself as we are.

    College will be the most important years in your life. It is in college that you will truly discover what learning is about. I want to tell you: “education is what you have left after all that is taught is forgotten”. What I mean by that is the materials taught isn't as important as you gaining the ability to learn a new subject, and the ability to analyze a new problem. That is really what learning in college is about—this will be the period where you go from teacher-taught to master-inspired, after which you must become self-learner.

    Follow your passion in college. Take courses you think you will enjoy. Steve Jobs says when you are in college, your passion will create many dots, and later in your life you will connect them. In his great speech given at Stanford, he gave the great example where he took calligraphy（书法）, and a decade later, it became the basis of the beautiful letters in Microsoft Word. So don't worry too much about what job you will have, and don't be too utilitarian（功利的）, and if you like Japanese or Korean, go for it! Enjoy picking your dots, and be assured one day you will find your calling, and connect a beautiful curve through the dots.

    Most importantly, make friends and be happy. College friends are often the best in life, because during college you are closer to them physically than to your mom and I. Pick a few friends and become really close to them-pick the ones who are honest and sincere to you. Don't worry about their hobbies, grades, looks, or even personalities. You have developed some real friendships in high school in your last two years, so trust your instinct, and make new friends.

    College is the four years where you have the greatest amount of free time, the first chance to be independent, the most possibilities to change and the lowest risk for making mistakes. So please treasure your college years! May Columbia become the happiest four years in your life, and may you blossom into just what you dream to be.

    A study based on data gathered by a NASA sensor has revealed China and India, the world's two most populous countries, are primarily responsible for making the Earth greener over the past two decades.

    The study, published on Feb 11 in the journal Natural Sustainability, has found that since 2000 the Earth's green leaf area has increased by over 5 million square kilometers. That's an area equivalent to the total of the Amazon rainforests. "China and India account for one-third of the greening, considering the general idea of land degradation (退化) in populous countries from overexploitation," said Chen Chi from Boston University, lead author of the study.

    The effect mainly comes from ambitious tree-planting programs in China and intensive agriculture in both countries, NASA said in a statement. China is the source of a quarter of the planet's increase in forest area, despite having only 6.6 percent of the world's vegetated (固定植被的)area, according to the study. Forest conservation and expansion programs account for 42 percent of the increase, and another 32 percent come from intensive agriculture of food crops, NASA said. While raising their green leaf areas, China and India have also greatly increased their food production through" multiple cropping" practices, where a field is replanted and crops are harvested several time each year. "Production of grains, vegetable, fruits and more have increased by about 35 to 40 percent since 2000 to feed their large population," NASA said.

    Over the past decades, China has made great efforts to green the land. In 1978, the central government launched a national-level forestation project-the Three North Shelterbelt Forest Program. By the end of 2017, the forest coverage rate among the regions in the project reached 13.57 percent, compared to 5.05 percent 40 years ago. In a greening project, Kubuqi Desert, seventh largest in the country, has seen one-third of its area covered by vegetation during the past three decades thanks to forestation efforts.

"Someone once asked me, 'What's the tool you would want to give any student'? And I said, 'A mask and snorkel （潜水通气管） set, "' the ocean biologist Thys says in a video. And Thys explains, "Ninety-eight percent of the living space on this planet is the ocean. It's worth a view. "

Thys has devoted her career to seeing the ocean and to helping others watch the great diversity of the underwater world. A big part of what motivates her work is the chance to let people develop a sense of respect for the grandness of the ocean, and to get people to participate in efforts to protect endangered ocean ecosystems. 

Since studying ocean biology, Thys has focused her research on how sea animals live. One animal she particularly studies is the ocean sunfish. "It's so different from any other fish, "says Thys. "It looks like a mistake. Where does the tail go?" Thys adds. "The sunfish provides an entry point to understanding more about the behavior of creatures in the ocean, and about how environmental changes impact underwater ecosystems. "

Thys's work also takes her above ground, where she's looking at ways to create new connections between human populations and natural environments to help address social and environmental challenges. For instance, she's working on nature's effects on mental well-being. 

Thys's passion for her work is evident in every lecture, video, and public appearance she makes. Using the media, Thys encourages people to learn about the ocean and love it. Due to many ocean research projects and activities from the media, Thys is up to her neck in work every day. She could hardly spare plenty of time for a good rest. Thys's devotion to her work as an ocean scientist and ecological warrior is infectious. She's a role model and an inspiring guide to ocean life. 

What will you do if you can't eat everything bought in the canteen(食堂)? {#blank#}1{#/blank#} According to a survey, what students waste every year could feed over 10 million people. 

{#blank#}2{#/blank#} According to Xinhua News Agency, the food wasted by Chinese people is about 50 million tons of grain every year, which could feed 200 million people. 

Food waste, which has become a global issue, serves as a mirror that reflects various cultural and social issues in different countries. In the west, for instance, consumerism, the belief that it's good to use a lot of goods and services, is often to blame for food waste. {#blank#}3{#/blank#}Chinese people are well known for being hospitable and generous. Many even feel that they lose face if their guests have eaten all the food. On campus, a generation of single children is less aware of the food waste issue. Students nowadays are well protected by their families and hardly have any concept of how much toil (辛劳) others go through in order to provide them with the food they eat. 

{#blank#}4{#/blank#}There are 925 million hungry people in the world. They don't have enough food to eat. And farmers work very hard to grow the crops. {#blank#}5{#/blank#}It's also important that everyone thinks about how they can do their bit to reduce food waste. Recently a campaign against food waste launched on line in China might make you think twice about being so wasteful.