Do you ever wonder why trees begin to bud (发芽) earlier in some cities? Scientists finally found the answer but it's not very pleasant. New science suggests a relationship between light pollution and the timing when trees produce buds, which signals the arrival of the spring season.

    Light pollution is defined by the Lighting Research Center as the unwanted consequence of outdoor lighting such as street lights. Excessive (过多的) man-made light at night results in disturbed natural cycles, and also prevents the observation of stars and planets at night. But its effect on the environment goes beyond that.

    By studying some trees, researchers found out that trees that are more exposed to artificial lighting at night bud up to 7.5 days earlier than those at the natural nighttime setting. And they found out that light had a more significant effect than temperature when the buds came out. The early budding may cause problems for insects, which feed on leaves, and the birds which then feed on them in turn. Professor Richard Ffrench-Constant, who helped lead the research, explained that more than the budding of trees, the study implies the danger to the balance of the ecosystem. “At the moment, caterpillars (毛毛虫) are timed to hatch to make the most of the opportunities to feed on freshly budded leaves, and birds hatch in time to feed on the young caterpillar,” he said.

    Migratory (迁徙的) birds are also negatively affected by light pollution. The glare might confuse them and make them lose their flying sense. The phenomenon might explain why some birds accidentally knock into buildings.

    Such results stress the need to pursue studies that aim to measure the effect of light pollution. If the issue were left to continue, it is estimated that by 2100, spring would begin almost a full month earlier than it does today.

    What do you think of cats? Some people think very lovely. But not all people love cats. Compared with dogs, cats seem to be very lazy and unfriendly. Besides, cats are not known for acts of selflessness (无私). But maybe we're wrong about them. Don't believe it? Then meet Pippa, a very unusual cat.

    The black-and-white cat was left in a box outside a shop and taken by the British RSPCA to the Jansa family in Whitstable, Kent. They really loved her character (性格) and decided to adopt (收养) it，but they never guessed she'd become a lifesaver.

    Eight-year-old Mia Jansa had diabetes and had become good at testing her blood during the day, as well as having something to eat or drink to bring her blood sugar levels back. But the danger was at night. Mia could easily experience hypoglycemic (低血糖症的) situations when she was asleep, which could cause even death.

    Soon after she was adopted, Pippa went into Mia's bedroom in the middle of the night and woke her up. When the child tested her blood sugar levels, she found they were dangerously low. Ever since, Pippa always visits Mia at night. If she can't get her to wake up, she raises the alarm.

    “Pippa does this of her own accord,” says Mia's mother Laura. “We don't make a request for caring because we don't want to encourage wrong alarms. She gets plenty of hugs. It gives me peace of mind and I know someone else is keeping an eye on Mia.”

    Now the family is so happy that they've chosen to adopt it in the first place.

    According to new research from the University of Cambridge in England, sheep are able to recognize human faces from photographs.

    The farm animals, who are social and have large brains, were previously known to be able to recognize one another, as well as familiar humans. However, their ability to recognize human faces from photos alone is novel.

    The recent study, the results of which were published in the journal Royal Society showed that the woolly creatures could be trained to recognize still images of human faces, including those of former President Barack Obama and actress Emma Watson.

    Initially, the sheep were trained to approach certain images by being given food rewards. Later, they were able to recognize the image for which they had been rewarded. The sheep could even recognize images of faces shown at an angle, though their ability to do so declined by about 15 percent - the same rate at which a human's ability to perform the same task declines.

    “Anyone who has spent time working with sheep will know that they are intelligent, individual animals who are able to recognize their handlers,” said Professor Jenny Morton, who led the Cambridge study. “We've shown with our study that sheep have advanced face-recognition abilities, comparable with those of humans and monkeys.”

    Recognizing faces is one of the most important social skills for human being, and some disorders of the brain, including Huntington's disease, affect this ability.

    “Sheep are long-lived and have brains that are similar in size and complexity to those of some monkeys. That means they can be useful models to help us understand disorders of the brain, such as Huntington's disease, which develops over a long time and affects cognitive abilities. Our study gives us another way to monitor how these abilities change.” Morton said.

    "Fast fashion" means clothes which are inexpensive but look like the latest designs. One reason for the success of fast fashion is the rise of the social media. A report by the investment research firm Bernstein found that Millennials—people born in the 1980s and 90s— wanted to wear a variety of clothes in the photos they posted on social media. As a result, many businesses which offer trendy and low-cost clothes are growing.

    But the situation is changing now. Maxine, a woman in her early thirties, looks in her closet full of clothes, but she has nothing to wear. She says she hates always shopping for what is in style.    Instead, she wants to buy fewer clothes that she can wear over and over. "Other people want the same thing." she says.

    So Maxine and a business partner, Soraya, started a "slow fashion" clothing company called Zady. "Slow fashion" means clothes that last a long time. They often feature classic colors and shapes, and are made from natural materials.

    The terms "fast fashion" and "slow fashion" are related to "fast food" and "slow food": fast food is still popular in the U.S., but many restaurants increasingly offer high-quality, more expensive and relaxed meals.

    Like slow food, slow fashion also aims to use sources that are good for the environment and workers. Maxine says people in her generation want to know where their clothes come from and who is making them. To answer Millennials' demand for information about the products they buy, Ms Maxine's company, Zady, includes details about the history of the brands. It also describes the process in which the clothes are made. Maxine says Zady aims to tell shoppers where their clothes come from, where they go, and how they impact the world.

    The international business H&M is answering Millennials' demands in another way. It has created a recycling program for clothes. Shoppers who bring clothes they no longer want to H&M stores can receive a discount on new things they buy. An H&M spokesman says, "We have a clear vision to avoid and minimize waste that goes into landfills."

    Stephen Hawking is one of the most famous scientists in this century. He was born in 1942. He's world well-known on space and time. Stephen was searching some very big questions, such as "How did the universe begin? How will it end?"

    Stephen was a student at Oxford University. He studied math and science. Then, at the age of twenty, he became sick. He was so young, but the doctors said to his family, "He has only two more years to live." As a matter of fact, the doctors were wrong – he didn't die. He can't walk but he uses a wheelchair. He can't feed himself and get in or out of bed himself. But he refused to give in to the condition. He talks with the help of a computer. After Oxford, Stephen went to Cambridge University. Three years later, in 1965, he became a doctor of philosophy(哲学).

    Because of his serious health problems, it was difficult for him to draw or to write. So he started to think in pictures. With this new way of thinking, he became one of the most famous scientists in the world. In 1981, he met the Pope(教皇) in Rome. They talked about his ideas. Then in 1988, he wrote his first important book, A Brief History of Time. It sold more than 5.5 million copies in 33 different languages. He was once invited to China, he impressed us with his self-confidence, humorous and witty(风趣的) conversation.(谈话)

When it comes to travel, sometimes wandering is one of the most exciting things you can do. In a time when travellers are both more adventurous and eco-conscious than ever, it's no surprise that there's a wealth of new vocabulary to describe how we travel, when we travel and how the experience makes us feel. Here are eight of our favourite travel words that you may not have heard before.

We've kicked off a blog with the staycation, "a holiday in one's own country". The term first became popular in the mid-2000s, when the global financial crisis meant people had less income to spend on flash holidays and instead searched for cheaper local choices. Since 2020, the staycation is experiencing a revival (复兴). Benefits of staycations include cheaper travel costs, no spending hours in the airport and, of course, no need to worry about whether your passport expired (过期) last year.

Once upon a time, if you wanted to meet new people on your travels, you could stay at a hostel or with a host on Airbnb. Now, you can couch surf. And not just in "the staying at various friends' houses until you find a new place to rent" sense: couch surfing is quickly becoming a hot new travel trend. Travellers can now choose to couch surf all across the world via a website which treats travel as a cultural exchange, allowing people to connect with willing hosts and crash on their sofas.

Given that single-use and climate strike were selected as the Collins 2018 and 2019 Words of the Year respectively, it's clear that the climate crisis is very much on everybody's mind. This desire to make more sustainable choices is also affecting the way we spend our vacation days. Ecotourism is another popular travel trend, defined as tourism that is designed to contribute to the protection of the environment. Examples of ecotourism include ditching short-haul flights, staying at eco-friendly resorts, or booking a staycation.