B

    Two weeks before my 12th birthday, my teacher asked me to conduct an experiment. When I mixed some powder together, they exploded. Molten liquid hit me in the face, but I felt no pain.

    I vividly remember standing there in a state of calm. I thought I was in a dream, but however hard I struggled to swim to the surface of consciousness, I couldn't wake up. I didn't understand how terrifying it was until I heard people saying, ＂Who's that?＂ That's when I knew I was unrecognizable.

    I was taken to hospital, but the doctors didn't know what to do with me. Later I was flown to Houston for surgery. Between the ages of 13 and 16, I had 40 operations. As each operation came and went, my vision would come back, then fade again. Eventually, it faded completely and I had what was left of my eyes removed for cosmetic reasons.

    Since then, I have lived in total darkness. Most blind people, even if they don't have any sight they're aware of, are still able to sense light. That gives them a sense of day and night. But not me. I absolutely lost that sense of time passing.

    For many years, I felt my sight loss darkening my life like the loss of my parents from which I would never recover. But when I was in my 40s, I realized I had to find a way to live. I trained to become a counselor, and that has helped me see my experiences in a different way. I can't fix people's broken lives — just like I can't fix my sight — but I can help them find a way to manage.

    Sometimes it feels as if all the struggles and negative experiences I've lived through were in fact a kind of preparation for helping others to make their own way towards the light.

    As he applied sunscreen to his young daughter's face, Dara O'Rourke, a professor of environmental and labor policy at the University of California, Berkeley, found himself wondering if the lotion(霜) was safe. He realized there was no readily available answer. The result—two years, a team of chemists, lots of testing and venture capital(风险投资) later—is GoodGuide. com. Launched in 2008, this is a website with a smart phone app that rates 140, 000 consumer products (only in America) according to their safety, environmental sustainability and the ethics of the firms that make them. Now GoodGuide has created a new “purchase analyzer” app designed to inform consumers not just about the values attached to products, but also about whether they are the virtuous(有信誉的) shoppers they say they want to be.

    Using the new app requires selecting a series of characteristics, which range from whether the user favours organic products to buying only from firms with a good human-rights record. Consumers then scan the bar code on a product with the camera in their smart phones. The app identifies it and checks in a database to score it. Much therefore depends on the quality of the data, which GoodGuide gathers from various sources, including government reports, scientific studies, and research by its own staff. If the product scores badly, the app will recommend an alternative item which is rated more highly. The app also tracks a consumer's purchases to see how well he lives up to his selected values, giving a sort of personal virtue rating.

    So far, GoodGuide has mostly been used by shoppers who are keen to know about any issues connected with products they buy. They are mothers concerned about a child's health, older people facing a chronic(慢性的) illness or supporters of a cause, such as animal rights. The hope behind the app is that the idea of finding out about a product's background will become the mainstream.

    Consumers rarely change their buying habits, even when provided with scientific and other data, says Mr O'Rourke. So he has drawn on insights from behavioral economics, which show shoppers can be greatly influenced by peer pressure and by information passed on to them by people they know. The app tries to take advantage of these pressures. The virtue rating will inform consumers how well they are doing according to the values they espouse(拥护). That measurement encourages them to do better. Soon, the rating will be able to be shared with others on social media sites such as Facebook, which could inspire a shopper to consume more thoughtfully.

    Children start out as natural scientists, eager to look into the world around them. Helping them enjoy science can be easy; there's no need for a lot of scientific terms or expensive lab equipment. You only have to share your children's curiosity. Firstly, listen to their questions. I once visited a classroom of seven-year-olds to talk about science as a job. The children asked me “textbook questions” about schooling, salary and whether I liked my job. When I finished answering, we sat facing one another in silence. Finally I said, “Now that we're finished with your lists, do you have questions of your own about science?”

    After a long pause, a boy raised his hand, “Have you ever seen a grasshopper （蚱蜢）eat? When I try eating leaves like that, I get a stomachache. Why?”

    This began a set of questions that lasted nearly two hours.

    Secondly, give them time to think. Studies over the past 30 years have shown that, after asking a question, adults typically wait only one second or less for an answer, no time for a child to think. When adults increase their “wait time” to three seconds or more, children give more logical, complete and creative answers.

    Thirdly, watch your language. Once you have a child involved in a science discussion, don't jump in with “That's right” or “Very good”. These words work well when it comes to encouraging good behavior. But in talking about science, quick praise can signal that discussion is over. Instead, keep things going by saying “That's interesting” or “I'd never thought of it that way before”, or coming up with more questions or ideas.

    Never push a child to “Think”. It doesn't make sense, children are always thinking, without your telling them to. What's more, this can turn a conversation into a performance. The child will try to find the answer you want, in as few words as possible, so that he will be a smaller target for your disagreement.

    Lastly, show; don't tell. Real-life impressions of nature are far more impressive than any lesson children can learn from a book or a television program. Let children look at their fingertips through a magnifying glass（放大镜）, and they'll understand why you want them to wash before dinner. Rather than saying that water evaporates（蒸发）, set a pot of water to boil and let them watch the water level drop.

    Do you know of anyone who uses the truth to deceive(欺骗)?When someone tells you something that is true, but leaves out important information that should be included, he can give you a false(假的) picture.

    For example, someone might say, ''I just won a hundred dollars on the lottery(彩票). It was great. I took that dollar ticket back to the store and turned it in for one hundred dollars!"

    This guy's a winner, right? Maybe, maybe not. We then discover that he bought $200 worth of tickets, and only one was a winner. He's really a big loser!

    He didn't say anything that was false, but he left out important information on purpose. That's called a half-truth. Half truths are not technically lies, but they are just as dishonest.

    Some politicians often use this trick. Let's say that during Governor Smith's last term, her state lost one million jobs and gained three million jobs. Then she seeks another term. One of her opponents says, “During Governor Smith's term， the state lost one million jobs!” That's true. However, an honest statement would have been, “During Governor Smith's term, the state had a net gain of two million jobs.”

    Advertisers will sometimes use half-truths. It's against the law to make false statements so they try to mislead you with the truth. An advertisement might say, “Nine out of ten doctors advised their patients to take Yucky Pills to cure toothache.”' It fails to mention that they only asked ten doctors and nine of them work for the Yucky Company.

    This kind of deception happens too often. It's a sad fact of life: Lies are lies, and sometimes the truth can lie as well.

    We Brits love the idea of a real Christmas tree but not so many of us like the realities of dragging (拖拽) a 7ft Norway Spruce through the house and leaving needles all over the place.

    If you count yourself among the reluctant group, then it may be time to go fake (假的) . After all, buying an artificial Christmas tree needn't mean accepting defeat. There's a huge range of choices and sizes, including pre-lit trees, which will save you the frustration of trying to string your own lights.

    Another big advantage of choosing an artificial Christmas tree is cost: artificial trees can last for decades, so they work out cheaper than paying for a real tree every year. Like now retailers (零售商) are offering great deals at the moment: at Tesco, there's 25 percent off artificial Christmas trees. Meanwhile, you can take advantage of the current 3 for 2 offer at Argos to fill your house with not one, not two, but three. You may perhaps partner up with friends who are also looking to invest.

    Of course, keep your tree for years and years and it will start to pay you back in terms of carbon footprint; however, a “real” one will always have to be transported, used and dealt with every year.

    Are there any downsides? Yes. You might think you're saving the planet, but a fake tree is actually not an environmentally friendly option. Most are made in factories in Asia, resulting in some serious air miles to reach the UK. They're made from metal and plastic, and many end their lives in landfill (垃圾填埋).

    Another problem with a fake tree is that they don't look very natural and of course you won't get that lovely pine smell either. You'll also need to find space for storage.

    Wolves strike fear into the hearts of many species, humans included. Our fear of them has brought them to the edge of dying out, as we have cruelly killed them as competitors and trouble-makers. But researchers are discovering that the very fear they put into prey（被捕食者）species is exactly what helps make ecosystems（生态）healthy.

    Yellowstone National Park is a typical example of just how wolves can help repair an ecosystem. An October 2018 study analyzed 40 years of research on large animals inside the park.

    "Yellowstone has benefited from the reintroduction of wolves in ways that we did not anticipate, especially the complexity of biological interactions（互动） in the park," explained Mark Boyce, a professor in the Department of Biological Sciences." We were really surprised at that and we'd never have seen these responses if the park hadn't adopted ecological-process management—allowing natural ecological processes to take place with least human intervention."

    After the wolves were re-introduced at Yellowstone, willow and cottonwood trees increased in number. The population of bears and bison also rose and what was once a ruling deer-wolf interaction is now more diverse.

    To learn more about just how wolves are beneficial, a short documentary from Quest explains how the presence of wolves influences the behavior of deer, which eventually makes entire ecosystems more biologically diverse and healthy. In this documentary, biologist Aaron Wirsing explored why wolves and other top predators （捕食者）were needed for diverse ecosystems to develop. Using a simple video camera, Wirsing is gaining a unique view point on predator-prey relationships and changing the way we think about wolves.

    The research is one more piece of evidence for why protecting these top predators is important not just for wolves as a species, but for hundreds of species at every level of an ecosystem. The fear they bring along may be the very angle that helps save them from dying out.