It is good to get in touch with your inner child from time to time，and obviously some people are willing to pay big money for the chance to do so in a proper environment．A Brooklyn-based adult preschool is charging customers between $333 and $999 for the chance to act like a kid again．

At Preschool Mastermind in New York adults get to participate in show—and—tell，arts—and—crafts such as finger paint，games like musical chairs and even take naps．The month-long course also has class picture day where the adults are expected to have a field trip and a parent day.30-year-old Michelle Joni Lapidos，the brain behind the adult preschool，studied childhood education and has always wanted to be a preschool teacher．She's always on the lookout for new ways to get people in touch with the freedom of childhood．A friend encouraged her to start the mastermind course instead．

    According to Candice，her blogger friend，Preschool Mastermind gives adults a chance to relearn and master the things that they failed to understand as children．“I realized all the significances of what we learn in preschool，”said founder Michelle Joni，“People come here and get in touch with their inner child．It's magical．We are bringing ourselves back to another place，another time with ourselves when we are more believing in ourselves，more confident and ready to take on the world.”

    “One person's here because they want to learn not to be so serious．”Michelle said．“Another's here to learn to be more confident.” She explained that most of the classes were planned．However，Joni added that while the planned activities were fun，it was often the spontaneous(自发的)moments that attracted students．“It's the things you don't plan for，the sharing between friends and learning from each other.''

    For a 400-year-old art form, opera had a bad fame: overweight actresses singing the words which were hard to understand in one of those romance languages you were supposed to learn in high school. And with tickets costing as much as＄145 a performance, opera goers also had a certain appearance in people's mind: rich, well-dressed and old.

    But now opera companies around the country are loosening their ties and kicking off their shoes in an attempt to keep opera alive and take it to a younger and not so wealthy audience.

    Opera producers have found that to attract this crowd, they need to associate opera with common people. Because young people don't or won't come to the opera, companies are bringing the opera to them, giving performances in such unusual places as parks, libraries and public schools.

    The Houston Grand Opera's choice is the public library, where it performs “mobile operas”, shortened version(剧本) of child-friendly operas. This summer's production is Hansel &Gretel. By performing smaller versions of large productions, producers are able to make people interested while keeping costs at a reasonable level. The San Francisco Opera, which will be celebrating its 75^th anniversary this year, is staging Cinderella free of charge, keeping costs down by employing students from its Young Artists' Training Program.

Wilderness

    "In wilderness(荒野) is the preservation of the world." This is a famous saying from a writer regarded as one of the fathers of environmentalism. The frequency with which it is borrowed mirrors a heated debate on environmental protection: whether to place wilderness at the heart of what is to be preserved. 

    As John Sauven of Greenpeace UK points out, there is a strong appeal in images of the wild, the untouched; more than anything else, they speak of the nature that many people value most dearly. The urge to leave the subject of such images untouched is strong, and the danger exploitation(开发) brings to such landscapes(景观) is real. Some of these wildernesses also perform functions that humans need—the rainforests, for example, store carbon in vast quantities. To Mr.Sauven, these "ecosystem services" far outweigh the gains from exploitation.

    Lee Lane, a visiting fellow at the Hudson Institute, takes the opposing view. He acknowledges that wildernesses do provide useful services, such as water conservation. But that is not, he argues, a reason to avoid all human presence, or indeed commercial and industrial exploitation. There are ever more people on the Earth, and they reasonably and rightfully want to have better lives, rather than merely struggle for survival. While the ways of using resources have improved, there is still a growing need for raw materials, and some wildernesses contain them in abundance. If they can be tapped without reducing the services those wildernesses provide, the argument goes, there is no further reason not to do so. Being untouched is not, in itself, a characteristic worth valuing above all others.

    I look forwards to seeing these views taken further, and to their being challenged by the other participants. One challenge that suggests itself to me is that both cases need to take on the question of spiritual value a little more directly. And there is a practical question as to whether wildernesses can be exploited without harm.

    This is a topic that calls for not only free expression of feelings, but also the guidance of reason. What position wilderness should enjoy in the preservation of the world obviously deserves much more serious thinking.

    A food chain is a simple way of explaining how each living thing gets its food. For example, a simple African food chain might consist of three parts: first, trees and bushes; second, giraffes; and third, lions. Each link in a food chain is food for the next link. Food chains always start with plants and end with animals.

    Plants are at the bottom of the food chain. Scientists call them producers, because they use light energy from the sun to produce food from carbon dioxide and water through photosynthesis（光合作用）. Animals, unlike plants, can't produce their own food. Instead, they must eat plants or other animals. This is why scientists call them consumers.

    Consumer animals fall into three categories. Herbivores（食草动物）eat only plants. Carnivores（食肉动物） eat only other animals. Omnivores eat both plants and animals. In addition to producers and consumers, there are also decomposers(分解者).These organisms, such as bacteria and fungi, feed on decaying(腐烂) matter. They help the food chain by speeding up the decaying process that releases minerals back into the soil to be absorbed by plants as nutrients.

    Most food chains have only four or five links in them. As you go up a food chain, the amount of energy at each level diminishes, because some of the energy is lost in the form of waste or is used up by the organism at the level. That is why it takes many plants, for example, to feed a few giraffes who in turn feed one lion.

    Most animals are part of many different food chains, because they must eat more than one type of food to satisfy their energy needs. All of these interconnected food chains form a more complex structure called a food web. Humans, for example, are at the center of a very complex food web, because we tend to eat many different types of plants and animals.

    Electronic book publishing has many of the same risks and opportunities as electronic music publishing. By delivering text direct to the reader's computer screen, the e-book could cut down costs, and allow creators to deal directly with their audience, by passing (绕开) traditional publishers and traders. But it also raises the possibility of mass piracy (盗版). Phil Rance, founder and managing director of Online Originals, a London-based e-book publisher, sums it up, "No one wants Napster (在线音乐服务) to happen to books."

    Indeed, the most popular MP3may have put the frighteners on an industry that generally operates some way behind the "bleeding edge". The Meta Group, a leading US-based market researcher, says publishers are far too concerned about protecting their rights, "We believe all the recent legal control over Napster is like putting a finger in a river that is already overflowing. Publishers need to deal with reality and come up with new ways to develop wide electronic distribution, asking the question: How can we use the certainty of wide distribution to our advantage."

    At the moment, most publishers would like to limit the use of e-books to the person who bought them, or to the computer used to download them. If that can be done, e-books become just an extra income stream in a publishing industry that would continue to operate the way it does today, according to Terry Robinson, business manager for Adobe's e-paper group. "If you've cracked the digital rights aspect, you've cracked the market." He says.

    Robert Nichols, Books Director at BOL agrees, "Rights management is absolutely important. Publishers just say that 'until copyright is secure, we are not going to talk'."

    Ride-hailing apps and robot cars promise to change how we get around and the effects are already being felt. Traffic in New York is slowing down. Jams are common in Manhattan, especially in its business districts. Daytime traffic in the busiest areas now moves almost 20% more slowly than it did five years ago.

    It seems a place ripe for wide use of ride-hailing apps that, you might think, would reduce some of the jams. However, those apps appear to be making things worse as traffic has slowed in line with the growing popularity of apps such as Uber and Lyft, a study by transport expert Bruce Schaller suggests.

    Over the four years of the study, the number of cars in Manhattan seeking ride-hailing fares increased by 81%. There are now about 68, 000 ride-sharing drivers across New York. That's about five times the number of the yellow cabs licensed to operate there, he found. There are so many drivers, his work suggests, who spend about 45% of their spare time just touring for fares. That is a lot of unused cars blocking a lot of busy streets.

    Simple physics explains why ride-sharing vehicles are causing, not curing jams, said Jarrett Walker, a public transport policy expert who has advised hundreds of cities about moving people.

    "Lots of people are deciding that, 'Oh, public transport is just too much trouble this morning,' or whenever, which causes a shift from it," he told the BBC. "That means moving people from larger vehicles into smaller ones, which means more vehicles to move the same people. Therefore, more traffic."

    Data gathered about ride-sharing drivers illustrates how they contribute to congestion (塞车), said Prof. Christo Wilson, a computer scientist at Northeastern University who has studied the services. "You can look at the traffic pattern for the Uber vehicles and it perfectly matches the peaks for the rush hour and the peak time of a day," he said. They are out there in force at the worst possible times.