How fit are your teeth? Are you lazy about brushing them? Never fear: An inventor is on the case. An electric toothbrush senses how long and how well you brush, and it lets you track your performance on your phone.

    The Kolibree toothbrush was exhibited at the International Consumer Electronics Show in Las Vegas this week. It senses how it is moved and can send the information to an Android phone or iPhone via a Bluetooth wireless connection.

    The toothbrush will be able to teach you to brush right (don't forget the insides of the teeth!) and make sure you're brushing long enough. “It's kind of like having a doctor actually watch your brushing on a day-to-day basis,” says Thomas Serval, the French inventor.

    The toothbrush will also be able to talk to other applications(应用) on your phone, so developers could, for example, create a game controlled by your toothbrush. You could score points for beating monsters(怪物) among your teeth. “We try to make it smart but also fun,” Serval says.

    Serval says he was inspired by his experience as a father. He would come home from work and ask his kids if they had brushed their teeth. They said “yes,” but Serval would find their toothbrush heads dry. He decided he needed a brush that really told him how well his children brushed.

    The company says the Kolibree will go on sale this summer, for $99 to $199, depending on features. The U.S. is the first target market.

    Serval says that one day, it'll be possible to replace the brush on the handle with a brushing unit that also has a camera. The camera can even examine holes in your teeth while you brush.

    Chinese President Xi Jinping stressed Wednesday that the socialist path China has followed is "correct," and it is the choice of the “history and people.”

    Citing(引用) the remarkable achievements China has made over the past 37 years when it initiated the reform and opening-up policy, Xi noted that it only took several decades for China to complete the journey the developed countries have gone through for centuries.

    “That fully shows that the Chinese people are following a correct path,” the president said while addressing a banquet hosted by Lord Mayor of the City of London Alan Yarrow on Wednesday evening.

    Meanwhile, he pledged that China will stay committed to a peaceful development path and does not accept the logic that a country will seek hegemony(霸权，领导权) once it gets strong.

    “No one and nothing — in any reason — can influence China's determination and will to pursue the path of peaceful development,” he said.

    In his speech, the president also explained in detail about the development of friendly relations between China and Britain, citing tea culture, literature, movies, TV dramas, football and cultural exchanges.

    He specifically referred to Shakespeare's influence on him by sharing the story of his youth time in the countryside, when he was deeply attracted by the master's works.

    “The China-Britain friendship has been deeply rooted in the hearts of our two peoples. And there is a solid foundation in public opinion and in society for the two countries to grow long-term relations,” he added.

    They wear the latest fashions with the most up­to­date accessories(配饰)．Yet these are not girls in their teens or twenties but women in their sixties and seventies. A generation which would once only wear old­fashioned clothes is now favouring the same high street looks worn by those half their age.

    Professor Julia Twigg，a social policy expert，said，“Women over 75 are now shopping for clothes more often than they did when they were young in the 1960s.In the 1960s buying a coat for a woman was a serious matter. It was an expensive item that they would purchase only every three or four years—now you can pick one up at the supermarket whenever you wish to. Fashion is a lot cheaper and people get tired of things more quickly.”

    Professor Twigg analysed family expenditure(支出)data and found that while the percentage of spending on clothes and shoes by women had stayed around the same—at 5 or 6 per cent of spending—the amount of clothes bought had risen sharply.

    The professor said.“Clothes are now 70 per cent cheaper than they were in the 1960s because of the huge expansion of production in the Far East. In the 1960s Leeds was the heart of the British fashion industry and that was where most of the clothes came from，but now almost all of our clothes are sourced elsewhere. Everyone is buying more clothes but in general we are not spending more money on them.”

    Angela Barnard，who runs her own fashion business in London，said older women were much more affected by celebrity(名流)style than in previous years.

She said，“When people see stars such as Judi Dench and Helen Mirren looking attractive and fashionable in their sixties，they want to follow them. Older women are much more aware of celebrities. There's also the boom in TV programmes showing people how they can change their look，and many of my older customers do yoga to stay in shape well in their fifties. When I started my business a few years ago，my older customers tended to be very rich，but now they are what I would call ordinary women. My own mother is 61 and she wears the latest fashions in a way she would never have done ten years ago.”

    For nearly a century before there was such a thing as a space program, a view of space was possible. People could see full views of the Moon, explore Mars(探测火星),and study the outer space beauty. All of this was made possible by a small group of artist-astronomers(天文艺术家) who worked to show people how other worlds in space might look.

    Lucien Rudaux, a French artist, was the first to use his artistic ability and his knowledge of astronomy in art. His paintings show a mixture of skilled observations, brilliant imagination and careful attention. As a result, many of his works have come surprisingly close to actual conditions on distant planets. His painting of Mars included moonlike craters(火山口) that were first photographed by the astronauts in 1965. His 1930 painting of a dust storm looks remarkably like a photograph of a storm taken by the astronauts in 1976.

    The artist-astronomers, including Rudaux, made people interested in outer space by painting what turned out to be exact portraits of the planets.

    It happened to me recently. I was telling someone how much I had enjoyed reading Barack Obama's Dreams From My Father and how it had changed my views (观点）of our President. A friend I was talking to agreed with me that it was, in his words, "a brilliantly (精彩地) written book". However, he then went on to talk about Mr. Obama in a way which suggested he had no idea of his background at all. I sensed that I was talking to a book liar.

    And it seems that my friend is not the only one. Approximately two thirds of people have lied about reading a book which they haven't. In the World Book Day's “Report on Guilty Secrets”. Dreams From My Father is at number 9. The report lists ten books, and various author: which people have lied about reading, and as I'm not one to lie too often (I'd hate to be caught out), I'll admit (承认) here and now that I haven't read the entire (全部的) top ten. But I am pleased to say that, unlike 42 percent of people, I have read the book at number one, George Orwell's 1984.I think it's really brilliant.

    The World Book Day report also has some other interesting information in it. It says that many people lie about having read Jane Austen, Charles Dickens, Fyodor Dostoevsky (I haven't read him, but haven't lied about it either) and Herman Melville.

    Asked why they lied, the most common reason was to "impress"（使留下深刻印象) someone they were speaking to. This could be tricky if the conversation became more in-depth!

    But when asked which authors they actually enjoy, people named J. K. Rowling, John Grisham, Sophie Kinsella (ah, the big sellers, in other words). Forty-two percent of people asked admitted they turned to the back of the book to read the end before finishing the story (I'll come clean: I do this and am astonished that 58 percent said they had never done so).

    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.