Since English biologist Charles Darwin published On the Origin of Species in 1859, scientists have vastly improved their knowledge of natural history. However, a lot of information is still of the speculation, and scientists can still only make educated guesses at certain things.

    One subject that they guess about is why some 400 million years ago, animals in the sea developed limbs (肢) that allowed them to move onto and live on land.

    Recently, an idea that occurred to the US paleontologist (古生物学家) Alfred Romer a century ago became a hot topic once again.

    Homer thought that tidal (潮汐的) pools might have led to fish gaining limbs. Sea animals would have been forced into these pools by strong tides. Then, they would have been made either to adapt to their new environment close to land or die. The fittest among them grew to accomplish the transition (过渡) from sea to land.

    Romer called these earliest four-footed animals “tetrapods”. Science has always thought that this was a credible theory, but only recently has there been strong enough evidence to support it.

    Hannah Byrne is an oceanographer (海洋学家) at Uppsala University in Sweden. She announced at the 2018 Ocean Sciences Meeting in Oregon, US, that by using computer software, her team had managed to link Homer's theory to places where fossil deposits (沉积物) of the earliest tetrapods were found.

    According to the magazine Science, in 2014, Steven Balbus, a scientist at the University of Oxford in the UK, calculated that 400 million years ago, when the move from land to sea was achieved, tides were stronger than they are today. This is because the planet was 10 percent closer to the moon than it is now.

    The creatures stranded in the pools would have been under the pressure of “survival of the fittest”, explained Mattias Green, an ocean scientist at the UK's University of Bangor. As he told Science, “After a few days in these pools, you become food or you run out of food... the fish that had large limbs had an advantage because they could flip (翻转) themselves back in the water.”

    As is often the case, however, there are others who find the theory less convincing. Cambridge University's paleontologist Jennifer Clark, speaking to Nature magazine, seemed unconvinced. “It's only one of many ideas for the origin of land-based tetrapods, any or all of which may have been a part of the answer,” she said.

    People from East Asia tend to have more difficulty than those from Europe in distinguishing facial expressions — and a new report published online in Current Biology explains why.

    Rachael Jack from University of Glasgow, said that rather than scanning evenly across a face as Westerners do, Easterners fix their attention on the eyes.

    "We show that Easterners and Westerners look at different face features to read facial expressions," Jack said. "Westerners look at the eyes and the mouth in equal measure, while Easterners favor the eyes and ignore the mouth."

    According to Jack and his colleagues, the discovery shows that communication of human emotions is more complex than previously believed. As a result, facial expressions that had been considered universally recognizable cannot be used reliably to convey emotions in cross­cultural situations.

    The researchers studied cultural differences in the recognition of facial expressions by recording the facial movements of 13 Western people and 13 Eastern people while they observed pictures of expressive faces and put them into categories: happy, sad, surprised, fearful, disgusted, or angry. They compared how accurately participants read those facial expressions using their particular eye movement strategies.

    It turned out that Easterners focused much greater attention on the eyes and made significantly more errors than Westerners did. "The cultural difference in eye movements that they show is probably a reflection of cultural difference in facial expressions," Jack said. "Our data suggests that while Westerners use the whole face to convey emotions, Easterners use the eyes more and the mouth less."

    In short, the data shows that facial expressions are not universal signals of human emotions. From here on, examining how cultural factors have diversified these basic social skills will help our understanding of human emotions. Otherwise, when it comes to communicating emotions across cultures, Easterners and Westerners will find themselves lost in translation.

    In his 402nd anniversary year, Shakespeare is still rightly celebrated as a great wordsmith （语言大师）and playwright （剧作家）.But he was not the only great master of dramatic writing to die in 1616, and he is certainly not the only writer to have left a lasting influence on theater.

    While less known worldwide, Tang Xianzu is considered China's greatest playwright and is highly spoken of in that country of ancient literary and dramatic traditions.

    Tang was born in 1550 in Linchuan, Jiangxi province, and pursued a low-key career as an official until, in 1598 and aged 49, he retired to focus on writing. Unlike Shakespeare's large body of plays, poems and sonnets （十四行诗），Tang wrote only four major plays: The Purple Hairpin （《紫钗记》），Peony Pavilion （《牡丹亭》），A Dream under the Southern Bough （《南柯记》），and Dream of Handan（《邯郸记》）. The Peony Pavilion is considered Tang's masterpiece. The latter three are constructed around a dream narrative, a device through which Tang unlocked the emotional dimension of human desires and ambitions and explored human nature beyond the social and political restrictions of that time.

    Tang lived toward the end of the Ming Dynasty（1368—1644）and the popularity of his works had a good reason. Similar to Shakespeare, his success rode the wave of a renaissance （复兴）in theater as an artistic practice. As in Shakespeare's England, Tang's works became hugely popular in China too. During Tang's China, the way, in which playlets were enjoyed and performed, changed. Kunqu opera, a form of musical drama, spread from southern China to the whole nation and became a symbol of Chinese culture. Combining northern tune and southern music, kunqu opera was known for its poetic language, music, dance movements and gestures. Tang's works benefited greatly from the popularity of kunqu opera, and his playlets are considered classics of kunqu opera.

    While Tang and Shakespeare lived in a world away from each other, there are many things they share in common, such as the humanity of their drama, their iconic and heroic figures, their love for poetic language, a lasting popularity and the anniversary during which we still celebrate them.

    You can use your smartphone to get pretty much anything delivered directly to your door almost immediately. The hardest part is the process of trying to work out if you should tip and if so, doing the quick math before you get to the door. And, you know well that you should tip about 15-20% at restaurants, but do the same rules apply to delivery drivers?

    The co-founder of Grubhub, Matt Maloney, pretty much set the standard for tipping delivery people in a Facebook post. He's a strong supporter of tipping, and Grubhub's website suggests a $5 or a 20% tip. Maloney also said this number should go up if you order during, say, a snowstorm.

    However, most other delivery services say on their websites that tipping is not required. Some services, like Door Dash, do suggest no tip on their checkout window. Many, like Amazon Prime Now, allow customers to change their tip amount after their delivery has been received to reflect the quality of service. These companies help customers save money but delivery drivers are upset. They deal with bad weather, heavy traffic, extreme tiredness, and more, all for a $1 tip. Many feel that if you'd tip your pizza boy or girl, you should tip your delivery driver.

    The Emily Post Institute (EPI)'s official suggestion falls in line with Maloney's: “10-15% of the bill, or $2-5 for pizza delivery depending on the size of the order and difficulty of delivery.”

    Just like servers in a restaurant, delivery drivers almost always rely on your tips for their income. Tipping is a long-standing cultural tradition in America. So, until drones (无人机) can deliver hot dogs straight to your door, it's best to tip the people riding through the city at all hours to bring you hot fresh food.

    "A bird with a broken wing will never fly as high. " I'm sure T. J, Ware was made to feel this way almost every day in school.

    By high school, T, J. was the most celebrated troublemaker in his town. Teachers literally cringed when they saw his name posted on their classroom lists.

    I met T. J. for the first time when all the students at school were attending ACE training. At first, he showed no interest in the discussion. But slowly, the interactive games drew him in. T. J. had some brilliant thoughts on those situations, which were welcomed by his group. By the end of the activity, the other students on the team were impressed with his concern and ideas and elected T. J. co-chairman of the team.

    When T. J. showed up at school on Monday morning, a group of teachers were expressing their disagreements to the school principal about his being elected co-chairman. The principal reminded them that the purpose of the program was to uncover any positive feeling and strengthen its practice until true change can take place. The teachers left the meeting, firmly convinced that failure was unavoidable.

    Two weeks later, T. J. and his friends led a group of 70 students to collect food They collected a school record: 2,854 cans of food in just two hours. The local newspaper covered the event with a full-page article the next day. That newspaper story was posted on the main bulletin board at school, where everyone could see it. 

    T. J. ,s picture was up there for doing something great.

    T. J. started showing up at school every day and answered questions from teachers for the first time.  The event he started now yields 9,000 cans of food in one day, taking care of 70 percent of the need for food for one year.

    T, J. reminds us that a bird with a broken wing only needs mending.  But once it has healed, it can fly higher than the rest. T. J. got a job. He became productive. He is flying quite nicely these days.

    People generally tend to pick out the best-looking fruits and vegetables when shopping for produce, but Canadian supermarket chain Loblaws is attracting customers with badly-shaped and faulty produce at the price of 30% lower than normal-looking ones.

    A trial run of the ugly food line, named "Naturally Imperfect", began with only apples and tomatoes to choose from. Consumer demand has been so huge that Loblaws is going to introduce more unsightly vegetables and fruit options like onions and mushrooms. The line is available at other stores, including Real Canadian Superstore and Your Independent Grocer.

    All the produce that will be sold through Naturally Imperfect would otherwise have been used in juices, sauces, or soups, or have not been harvested at all. The director Dan Branson explained that this program benefited both food producers who would otherwise have to let abnormal harvest go to waste, and consumers who could buy fresh produce at low prices. And he was right, given how popular the line has become.

    "It really went well beyond our expectation," Branson said. "I think it really spoke to the fact that Canadians are out there really looking for some options."

    Of course, Canadians know that beauty is more than skin deep, but they also recognize that they can get the same flavor and nutritional benefits in spite of appearances. The positive response to the initial offering of apples and potatoes showed the opportunity to expand the line and offer more options at a greater price to Canadian families.

    "If you grow produce in your backyard, there will be a lot of produce that won't look as pretty as what you will see in a grocery store," said Branson. "And nature doesn't grow everything perfectly. I'd like to think if somebody were to take a No Name Naturally Imperfect apple, put right beside a No.1 apple, close their eyes and eat them, there would be no difference."