Over the last week, a "poisonous kale（甘蓝菜）" theory has been going widespread after an article warned that the vegetable was associated with a variety of medical conditions. It's time to separate fear from fact on the health benefits of kale.

    As a member of the cabbage family, kale is low in calories and rich in nutrients and minerals, especially vitamin A,C and K. Consumed for thousands of years, it's been a health plus for millions of eaters throughout the world.

    However, numerous web articles have reported on some evidence offered by a medicine researcher. The researcher found that thallium（铊）was detected in a few people who were heavy consumers of kale. Thallium is a heavy metal often found in trace amounts（微量）in soil and minerals. His conclusion was that these medical conditions were connected to the impact that trace amounts of thallium detected in some kale samples had on the body.

    I don't think the conclusion is based on a strict scientific basis. It's essential to point out that the original report was in a web magazine, not a scientific journal which is subject to peer review by other scientists. A scientific review includes a careful evaluation of how the findings and conclusions were made. Certain factors are critical before an evidence-based conclusion can be made, such as: how many people were in a study; how well controlled were other factors; how much kale was consumed and for how long; how much thallium was in the kale.

    It is a fact that kale and other vegetables can absorb thallium from the soil. But the ability for a plant to absorb traces of a chemical does not automatically make it harmful to your health. And even finding measurable amounts of thallium in someone's body doesn't imply that the thallium is causing an ill health effect, according to the CDC.

    But we can still learn a lesson from this. Plants grow in soil. Growers must continue to be careful in monitoring the quality of their soil. And what about consumers? Eat your kale—and include lots of other colorful fruits and vegetables. As with all things in nature, variety is key for good health.

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    With the Chinese language growing in popularity,the UK government plans to invest（投资）10 million pounds to help more kids learn Mandarin（普通话）.Do you think it is necessary for the UK pupils to learn Mandarin?Some people share their opinions online.

    Ted(UK): The learning of any language can be valuable and rewarding,but it is not suitable for everyone. Chinese is a difficult language to learn and the UK has a poor reputation for teaching foreign languages.Why should they learn Chinese when most people in the world speak English?

    Mark(US): I studied French for 2 years in high school and German for 4 years in college.I studied Mandarin informally for about 4 months before moving to China.Now I speak Mandarin every day as my wife doesn't speak English.But it is far from being fluent.Learning additional languages is a great thing,which offers a different perspective on the world around us.Nowadays,it's almost necessary to be able to speak more than just your native tongue.

    George(UK): No,unless they're taught from a very early stage of childhood.Mandarin is so difficult.If China really is going to dominate the world,it'll have to do so by speaking the world's dominant language—English.

    Sam(UK): I don't think Chinese will become as widely spoken throughout the world as English.It is too difficult to learn as a second language.To learn Chinese you completely have to devote yourself to learning how to write and read it.If you have to learn it besides other subjects you can't be good at it.But Chinese will become more popular, and that is a good thing.

    Chinese people are, quite rightly, proud of their food. However, when foreigners like Britons and Americans think of Chinese food, their impression of it is different to what you might think.

    Growing up in the UK, the Chinese food I was used to eating was food I now recognize as being from Guangdong. For example, a typical dish I would order would be pork in sweet and sour sauce, probably with some rice and spring rolls on the side. This is the type of food we generally eat because most Chinese immigrants(移民) to the UK have come from Guangdong. You can tell, because when most British people try to copy the sound of Chinese, they actually copy the sound of Guangdong people—hearing the real Putonghua is sometimes a shock to British people who have grown up thinking it sounds completely different!

    British attitudes to Chinese food may be changing, though. Chinese-American chef Ken Hom has been on British TV for 30 years, and he told BBC Food: "Chinese food at the beginning of the 80s (in the UK) was sweet and sour pork, mainly. Most Brits had the unchangeable view of Chinese food… Now you are seeing more local Chinese food from Sichuan, Hunan and other areas of China. It is no longer just Guangdong food." Similarly, to most Americans, Chinese food doesn't go too far past orange chicken and fortune cookies, but more Chinese local dishes are becoming successful, especially in big cities like New York.

    Attitudes have not quite changed completely, though. Many foreigners who live in China will be familiar with this question from a relative back at home: "Have they given you dog yet?" Yes, perhaps because people still know too little about Chinese culture, many people believe that Chinese people love to eat dog meat. And of course, some people do eat dogs, which to Americans is like "eating a member of one's family" according to Vision Times. Also, Chinese people eat many other things people in the West do not—chicken claws, duck heads and some animals' organs.

    But what do foreigners think when they come to China and taste real Chinese food? You'll be glad to know that in my experience, the impressions have been very good.

    With the development of our society, cell phones have become a common part in our lives. Have you ever run into a careless cell phone user on the street? Maybe they were busy talking, texting or checking updates on WeChat without looking at what was going on around them. As the number of this new "species" of human has kept rising, they have been given a new name—phubbers (低头族).

    Recently a cartoon created by students from China Central Academy of Fine Arts put this group of people under the spotlight. In the short film, phubbers with various social identities bury themselves in their phones. A doctor plays with his cell phone while letting his patient die, a pretty woman takes a selfie (自拍) in front of a car accident site, and a father loses his child without knowing about it while using his mobile phone. A chain of similar events finally leads to the destruction(毁灭) of the world.

    Although the ending of the film sounds unrealistic, the damage phubbing can bring is real. Your health is the first to bear the effect and result of it. "Always bending your head to check your cell phone could damage your neck," Guangming Daily quoted doctors' words. "The neck is like a rope that breaks after long-term stretching." Also, staring at cell phones for a long time will damage your eyesight gradually, according to the report.

    But that's not all. Being a phubber could also damage your social skills and drive you away from your friends and family. When getting together with family or friends, many people prefer to play their cell phones while others are chatting happily with each other and this creates a strange atmosphere, Qilu Evening News reported.

    It can also cost your life. There have been lots of reports on phubbers who fell to their death, suffered accidents, and were robbed of their cell phones in broad daylight.

    It was a shock and a painful lesson for many people when the police announced the cause of a bus accident in Chongqing on Oct 28. Video footage (片段) from inside the bus suggested that after a passenger missed her stop and asked the driver to stop, but he refused. She began hitting him over the head with her cell phone. During the conflict, the driver lost control of the bus and it jumped into the Yangtze River, causing 15 deaths.

    Zheng Chuankai, a lawyer in Beijing, said the accident showed that it was important that those who cause danger to public safety face severe punishment. Such attacks are inhuman but common. In fact, it is not rare to hear of passengers attacking bus drivers in China. This month, a local court in Shenyang, Liaoning province, sentenced three people to up to three years in prison for endangering public safety by distracting bus drivers, Xinhua reported. “Passengers who interfere (妨碍) with bus drivers are endangering public safety, which is equal to serious crimes like arson (纵火) and poisoning.” Liu Changsong，a Beijing lawyer, told the Global Times.

To prevent similar cases from happening, many Chinese cities have taken measures to keep bus drivers safe. Dozens of cities including Beijing, Xi'an, Wuhan, Changsha and Nanning have plans to add safety fences to buses to protect drivers from any interference by passengers.

    The bus operator in Quanzhou, Fujian Province, has invited psychologists to teach drivers how to manage their emotions when facing an angry passenger. These measures are necessary, but they are not enough.

    “Public security is closely connected with social morality (道德). People should obey the law, be more self-disciplined and sensible.”

    Many countries have introduced measures to deal with the problem of violence against bus drivers. On every bus in the US state of New Jersey, a sign on the back of the driver's seat warns passengers that anyone attacking a driver can be fined or put into prison.

    In London, the local government has launched a program to train drivers to deal with angry passengers and avoid potential conflicts.

    I was in the middle of the Amazon (亚马逊) with my wife, who was there as a medical researcher. We flew on a small plane to a faraway village. We did not speak the local language, did not know the customs, and more often than not, did not entirely recognize the food. We could not have felt more foreign.

    We were raised on books and computers, highways and cell phones, but now we were living in a village without running water or electricity It was easy for us to go to sleep at the end of the day feeling a little misunderstood.

    Then one perfect Amazonian evening, with monkeys calling from beyond the village green, we played soccer. I am not good at soccer, but that evening it was wonderful. Everyone knew the rules. We all spoke the same language of passes and shots. We understood one another perfectly. As darkness came over the field and the match ended, the goal keeper, Juan, walked over to me and said in a matter-of-fact way, "In your home, do you have a moon too?" I was surprised.

    After I explained to Juan that yes, we did have a moon and yes, it was very similar to his, I felt a sort of awe (敬畏) at the possibilities that existed in his world. In Juan's world, each village could have its own moon. In Juan's world. the unknown and undiscovered was vast and marvelous. Anything was possible.

    In our society, we know that Earth has only one moon. We have looked at our planet from every angle and found all of the wildest things left to find. I can, from my computer at home, pull up satellite images of Juan's village. There are no more continents and no more moons to search for, little left to discover. At least it seems that way.

    Yet, as I thought about Juan's question, I was not sure how much more we could really rule out. I am, in part, an ant biologist, so my thoughts turned to what we know about insect life and I knew that much in the world of insects remains unknown. How much, though? How ignorant (无知的) are we? The question of what we know and do not know constantly bothered me.

    I began collecting newspaper articles about new species, new monkey, new spider…, and on and on they appear. My drawer quickly filled. I began a second drawer for more general discoveries: new cave system discovered with dozens of nameless species, four hundred species of bacteria found in the human stomach. The second drawer began to fill and as it did I wondered whether there were bigger discoveries out there, not just species, but life that depends on things thought to be useless, life even without DNA. I started a third drawer for these big discoveries. It fills more slowly, but all the same, it fills.

    In looking into the stories of biological discovery, I also began to find something else, a collection of scientists, usually brilliant occasionally half-mad, who made the discoveries. Those scientists very often see the same things that other scientists see, but they pay more attention to them, and they focus on them to the point of exhaustion (穷尽), and at the risk of the ridicule of their peers. In looking for the stories of discovery, I found the stories of these people and how their lives changed our view of the world.

    We are repeatedly willing to imagine we have found most of what is left to discover. We used to think that insects were the smallest organisms (生物), and that nothing lived deeper than six hundred meters. Yet, when something new turns up, more often than not, we do not even know its name.