World leaders from nearly 200 countries have signed an important historic agreement to fight global climate change. The agreement came after two weeks of talks between the leaders at the 21st Conference in Paris, France.

    As part of the Paris agreement, countries said they would cut down on pollution However, according to the terms of the deal, countries that don't do this will not be punished, or fined. Instead，the document is meant to show that governments around the world take climate change seriously and are willing to work together to fight global warming.

    World leaders have met many times to discuss climate change. But, the 21st Conference of Parties, or COP21, which began on November 30 in Paris, was the first time they agreed on a global, legal pact (协定).

    Before the conference, each nation was asked to create plans on how to reach the shared goal. The pact that was signed allows countries to decide the best way to cut down their gas pollution. No matter how they decide to go green, each country must report honestly on all of their efforts. Every five years, nations must look at the work they've done and submit new plans on how they will improve over the next five years.

    In the pact, the countries pledge（承诺）to limit the amount of greenhouse gases emitted（排放） by human activity to the levels that trees，soil and oceans can absorb naturally. It urges countries to spend trillions of dollars on creating new energy sources, like solar and wind power. It also requires countries to raise at least $ 100 billion each year to help developing countries.

    However, critics of the pact say it is not detailed enough, and doesn't include specifics about how the plan will be enforced and how improvements will be measured. The pact does include one large, specific goal: how countries will aim to keep global temperatures from rising more than 3.60℉(20℃) by 2100.

    Nonetheless，the agreement is considered by many world leaders to be a major victory. The U. N. has been working more than two decades to convince governments to work together to reduce man-made emissions.

    “History will remember this day,” U. N. Secretary General Ban Ki-moon said. “The Paris agreement on climate change is a monumental success for the planet and its people.”

Do you believe that things are connected for no scientific reason at all? For example, do you avoid saying the word "four" to avoid bad luck? If so, you have a superstition (迷信). And you're not alone – all kinds of people have them.

For example, Portugal's soccer superstar Cristiano Ronaldo always steps onto the pitch (球场) with his right foot first, according to The Telegraph. And sports players are not alone in having superstitions. A visitor once asked the Nobel Prize winning scientist Niels Bohr whether he really believed that the horseshoe he'd hung at his country home was lucky. "Of course not," the Danish physicist said. "But I understand it's lucky whether you believe in it or not."

One recent study found that even scientists at MIT and other top US schools tended to look for a meaning in natural events, similar to the connection between stepping on the pitch and playing soccer well, according to The Atlantic. When the researchers gave the scientists little time to answer questions, they were twice as likely to agree with statements such as "Trees produce oxygen so that animals can breathe" as they were when they had more time to think about their reply.

It seems that fear can make people think differently in this way, too. In a British study, students imagined meeting a "witch" who said she would cast (施魔法) an evil spell(符咒) on them. About half said a scientist should not be worried about the spell. Yet each of them said that, personally, they wouldn't let the witch do it to them.

So why are so many of us superstitious? Well, it seems to be our way of dealing with the unknown. "Many people quite simply just want to believe," Brian Crank, a professor of psychology at Missouri Western State University, said in a 2008 interview. "The human brain is always trying to work out why things happen, and when the reason is not clear, we tend to make up some pretty bizarre (古怪的) explanations."

    And these explanations aren't completely unhelpful. In fact, superstitions can sometimes work and bring real luck, according to psychologists at the University of Cologne in Germany in the May 2010 issue of the journal Psychological Science. They found that believing in something can improve performance on a task like an exam.

    So, what about you? What superstitions do you follow to keep you safe and successful?

    Years ago, students applying to colleges and universities had to have their applications and personal essays printed out and then “snail-mailed”. Flash forward to today's world of Facebook, Instagram and WeChat, where photos, videos and mobile phones rule. Fortunately, several new tools are making it easier for college applicants to use technology to show off their personalities, skills and creativity.

    ZEEMEE

    One of the more popular innovations in college applications is ZeeMee, a free mobile app that allows students to upload personal profiles and videos to create visual resumes. More than 220 colleges and universities offer a ZeeMee option as part of the application process. The video can show the unique creative aspects of the applicants.

THE COALITION LOCKER

    Another relatively new tool comes from the Coalition for Access, Affordability and Success, now used by more than 110 member colleges and universities. Among the group's stated goals are getting students engaged in college prep early and using technology to create a supportive application process that encourages reflection and self-discovery.

    Students who sign up for the free platform get access to a digital “locker”, which they can use all through high school to save class papers, artwork, newspaper stories, videos and photos to share with colleges when they eventually apply.

    VIDEO — CHAT INTERVIEWS

    At some schools, an interview with an admission officer is an important part of the application process. To make it easier, several virtual interviewing tools have popped up, such as a video-based platform from Kira. More than 140 universities worldwide use Kira's video assessment tool to conduct real-time interviews with prospective students. During the interview, candidates are shown the questions prerecorded by the particular school and must respond in real time by talking into the camera on their laptop or phone. In addition to showing their ability, to speak fluently in English and think on their feet, it helps admission officers determine the “motivation, commitment and drive” of applicants.

    UNIQUE SCHOOL TOOLS

    Some universities have come up with their own ways to allow students to show their skills and personalities. For example, the Massachusetts Institute of Technology, encourages applicants to display their technical abilities and creativity by submitting a “Maker Portfolio” —a written or videotaped description of a project that shows creative and problem-solving skills. While a new app would fit the bill, the project could be anything from an origami design to a potato cannon.

    This is a family story my father told me about his mother, my grandmother.

In 1949, my father had just returned home from the war. On every American highway you could see soldiers in uniform hitchhiking home to their families, as was the custom at that time in America.

    Sadly, the thrill of his reunion with his family was soon overshadowed. My grandmother became very ill and had to be hospitalized. It was her kidneys, and the doctors told my father that she needed a blood transfusion immediately or she would not live through the night. The problem was that grandmother's blood type was AB-, a very rare type even today, but even harder to get then because there were no blood banks or air flights to ship blood. All the family members were typed, but not one member was a match. So the doctors gave the family no hope; my grandmother was dying.

    My father left the hospital in tears to gather up all the family members, so that everyone would get a chance to tell grandmother goodbye. As my father was driving down the highway, he passed a soldier in uniform hitchhiking home to his family. Deep in grief, my father had no inclination at that moment to do a good deed. Yet it was almost as if something outside himself pulled him to a stop, and he waited as the stranger climbed into the car.

    My father was too upset to even ask the soldier his name, but the soldier noticed my father's tears right away and inquired about them. Through his tears, my father told this total stranger that his mother was lying in a hospital dying because the doctors had been unable to locate her blood type, AB-, and if they did not do it before nightfall, she would surely die.

    It got very quiet in the car. Then this unidentified soldier extended his hand out to my father, palm up. Resting in the palm of his hand were the dog tags from around his neck. The blood type on the tags was AB-. The soldier told my father to turn the car around and get him to the hospital.

    My grandmother lived until 1996, 47 years later, and to this day no one in our family knows the soldier's name. But he is always remembered by us.

    Can you trust your very first childhood memories? Maybe not, a new study suggests.

    Past researches show that people's earliest memories typically form around 3 to 3. 5 years of age. But in a recent survey of more than 6,600 people, British scientists have found that 39 percent of participants claimed to have memories from age 2 or younger. These first memories are likely false, the researchers said. This was particularly the case for middle -aged and older adults.

    For the study, researchers asked participants to describe their first memory and the age at which it occurred. Participants were told they had to be sure the memory was the one that had happened. For example, it shouldn't be based on a photograph, a family story or any source other than direct experiences. Then the researchers examined the content, language and descriptive details of these earliest memories and worked out the likely reasons why people would claim to have memories from an age when memories cannot form.

    As many of these memories dated before the age of 2, this suggests they were not based on actual facts, but facts or knowledge about their babyhood or childhood from photographs or family stories. Often these false memories are fired by a part of an early experience, such as family relationships or feeling sad, the researchers explained.

    "We suggest that what a rememberer has in mind when recalling fictional early memories is …a mental representation consisting of remembered pieces of early experiences and some facts or knowledge about their own babyhood or childhood," study author Shania Kantar said in a journal news release, "Additionally, further details may be unconsciously inferred or added. Such memory-like mental representations come over time, to be collectively experienced when they come to mind, so for the individual, they quite simply are memories, which particularly point to babyhood."

    "Importantly, the person remembering them doesn't know this is fictional," study co-author Martin Conway said "In fact, when people are told that their memories are false they often don't believe it."

For nearly two decades, a thin, sun-burnt postal worker could frequently be seen carrying packages along a dangcrous mountain trail in the Taihang Mountains.

The 10-kilometer-long route, which is between 20 centimeters and 1 meter wide, is known as the "cat road" by locals, meaning that it is so dangerous that only cats could walk on it. Whereas, Zhao Yuefang, a postal worker in Ewu township in Huguan county, Shanxi province, had to walk the route every day to deliver mail.

Every day at the crack of dawn, he would start his journey along the "cat road". From picking up the day's post to delivering it to villagers and returning along the same route, it took Zhao four days. During rainy and snowy seasons, the mountain road, part of which hugs the cliffs, would become slippery and dangerous. One day in the winter of 2003, the "cat road" was covered in thick snow and he slipped off the trail. Fortunately, he was able to stop his sharp descent by grabbing a tree branch and slowly managed to climb to safety.

By 2012, Zhao had walked more than 300,000 km and delivered over 800,000 pieces of mail. Born and raised in the deep mountains, Zhao truly understands the significance of mail deliveries to villagers. "They depend on the mail to keep in touch with the outside world," he said. "Their sheer joy written on their face while receiving any post struck me," he added.

In 2012, a 67-km-long tourist highway was built and gone were those days when Zhao risked his life to walk on the "cat road". But Zhao was even busier than before. "The number of packages I handle daily now exceeds the number I used to deal with in the past," said Zhao, adding that villagers are turning to online shopping and ordering more and more goods by post.