The fence was long and high. He put the brush into the whitewash and moved it along the top of the fence. He repeated the operation. He felt he could not continue and sat down.

    He knew that his friends would arrive soon with all kinds of interesting plans for the day.

    They would walk past him and laugh. They would make jokes about his having to work on a beautiful summer Saturday. The thought burned him like fire.

    He put his hand into his pockets and took out all that he owned. Perhaps he could find some way to pay someone to do the whitewashing for him. But there was nothing of value in his pockets—nothing that could buy even half an hour of freedom. So he put the bits of toys back into his pockets and gave up the idea.

    At this dark and hopeless moment, a wonderful idea came to him. It filled his mind with a great, bright light. Calmly he picked up the brush and started again to whitewash.

    While Tom was working, Ben Rogers appeared. Ben was eating an apple as he walked along the street. As he walked along it, he was making noises like the sound of a riverboat. First he shouted loudly, like a boat captain. Then he said “Ding－Dong－Dong”,“Ding－Dong－Dong” again and again, like the bell of a riverboat. And he made other strange noises. When he came close to Tom, he stopped.

    Tom went on whitewashing. He did not look at Ben. Ben stared a moment and then said: “Hello! I'm going swimming, but you can't go, can you？”

    No answer. Tom moved his brush carefully along the fence and looked at the result with the eye of an artist. Ben came nearer. Tom's mouth watered for the apple, but he kept on working.

    Ben said, “Hello, old fellow, you've got to work, hey？”

    Tom turned suddenly and said, “Why, it's you, Ben! I wasn't noticing.”

     “Say—I'm going swimming. Don't you wish you could? But of course you'd rather work—wouldn't you? Of course you would.”

    Tom looked at the boy a bit, and said, “What do you call work？”

     “Why, isn't that work？”

    Tom went back to his whitewashing, and answered carelessly.

     “Well, maybe it is, and maybe it isn't. All I know is, it suits Tom Sawyer.”

     “Oh come, now, you don't mean to say that you like it？”

    The brush continued to move.

     “Like it? Well, I don't see why I shouldn't like it. Does a boy get a chance to whitewash a fence every day？”

    Ben stopped eating his apple. Tom moved his brush back and forth, stepped back to look at the result, added a touch here and there, and stepped back again. Ben watched every move and got more and more interested. Soon he said，“Say, Tom, let me whitewash a little.”

    Tom thought for a moment, and was about to agree, but he changed his mind.

     “No—no—it won't do, Ben. You see, Aunt Polly wants this fence to be perfect. It has got to be done very carefully. I don't think there is one boy in a thousand, maybe two thousand, that can do it well enough.”

     “No—is that so? Oh come, now—let me just try. Only just a little.”

“Ben, I'd like to, but if it isn't done right, I'm afraid Aunt Polly ”

     “Oh, I'll be careful. Now let me try. Say—I'll give you the core of my apple.”

     “Well, here—No, Ben, now don't. I'm afraid …”

     “I'll give you all of it.”

    Tom gave up the brush with unwillingness on his face, but joy in his heart. And while Ben worked at the fence in the hot sun, Tom sat under a tree, eating the apple, and planning how to get more help. There were enough boys. Each one came to laugh, but remained to whitewash. By the time Ben was tired, Tom sold the next chance to Billy for a kite; and when Billy was tired, Johnny bought it for a dead rat—and so on, hour after hour. And when the middle of the afternoon came, Tom had won many treasures.

    And he had not worked. He had had a nice idle time all the time, with plenty of company, and the fence had been whitewashed three times. If he hadn't run out of whitewash, Tom would have owned everything belonging to his friends.

    He had discovered a great law of human action, namely, that in order to make a man or a boy want a thing, it is only necessary to make the thing difficult to get.

    One evening at a busy crossroads, I noticed a sister struggling to keep her little kid under control while she talked on the pay phone. She wanted him to stay still next to her, but he wanted to run and play by the road, close to rushing buses and taxis. One could sense the woman's frustration, that she was pulled in too many directions: She was angry at the person on the telephone and shouting at the younger that she would “snap（折断）his leg” if he moved again. As I waited for the traffic light to change, the child began to complain and struggle to free himself from the woman's grasp. She dropped the phone, seized（抓住）the neck of his tiny. T-shirt and gave him a back-hand blow across the face that I know made his little head spin.

    The light changed, and passers-by continued on their way. But I stood there, fixed to the pavement. I knew this extremely upset woman would carry through on her threat of violence to the child. Before, I had wanted to get close to her and offer to watch the youngster while she dealt with the troubling situation on the phone. Now I wanted to comfort the little boy. I also wanted to speak to the sister to calm her and to caution（告诫）her, as I wish someone had cautioned me when I was passing my pain on to my daughter and causing her emotional suffering. But I was chicken. I thought, she may think I'm out of line, or I may be her next target.

    Often I've thought about that child and the many others abused（虐待）by adults. I wonder how they will internalize（使……藏在心底）their pain, and if it will crush their spirits. Will this little boy grow up to be an abusive man? Will he be gloomy（阴郁的，沮丧的）and withdrawn（孤僻，内向的）? Will he find it hard to communicate with women, with other men? Or will he survive and be sensitive, caring and determined not to continue the cycle?

    There is too much cruelty（残忍）in the world, too much cruelty between people. I tremble at the increasing verbal（言语的）bitterness and violence among Black girls, and among young mothers trying to discipline their children. This behavior isn't class-or age-related: I hear sharp words from Black women from all walks of life who are overworked and stressed out and have grown impatient. At times I, too, become impolite to others, or, like the sister on the phone, strike out at（抨击）those closest to me.

    Often we're tired because we've made the wrong choices. Young girls who still need mothering are loaded with children. We sisters easily get hurt and annoyed when we don't compromise with our own sense of self. Our personal fulfillment requires knowing what is best for us, setting our boundaries（界限）and keeping them undamaged. We will always be asked to do more than we are comfortable doing. When we know our boundaries, we can decline comfortably. People—and we ourselves—will act in ways we don't like. But they, like us, are still worthy of love.

    Whatever irritates（激怒）us about a person should be examined. Is the person reflecting behavior in us that needs to be changed? Often, when I find people irritating, I find they mirror something about me that I need to correct.

    What's needed in our personal relationships is a return to gentleness and tolerance（容忍）. We must allow one another our learning experiences. Just as violence results to violence, verbal violence—the hard words and sharp tones we use to release inner stress—adds to the distance between us.

    What we people of African root must do to become, and continue to be strong begins with love, sensitivity and our ability to work together. We Black women have these spiritual resources in abundance（丰富）. Now we must encourage them to create a peaceful place—for ourselves, our children, our men.

    Sharon, Aged 22

    The most important thing to keep in mind when going into high school is to be yourself. Besides, I don't know what your middle school was like, but high school teachers will not care about things such as how much homework you already have in one night. It's best to just learn to deal with things and manage your time wisely so you can achieve everything you need to.

    Frank, Aged 21

    I think almost every kid feels both nervous and excited before their first day. You will probably love it. I know I did. You should join in some sports or activities that will make your high school experience more enjoyable. Good luck!

    David, Aged 19

    I'm not going to lie. The first day is kind of frightening. But you'll get used to it. Don't be afraid of anyone; upperclassmen will pick on you more if you let them know you're afraid. Just take it easy. Making some friends and staying with them will greatly help you get used to high school quickly. After the first week it's really not bad at all. Don't worry.

    Eddie, Aged 20

    When I started high school I was really nervous too, especially since I had been homeschooled all through middle school and didn't really know anyone. I suppose the best advice would be to just relax. The first couple of days can be a little bit hard, but things will become easier before you know it.

    "Mummy, I don't know what to play with." Steve interrupts his mother, who is talking to a friend, for the fourth time. "You've got a room full of toys!" his mother says, impatiently. In fact it is the jumble of toys which is to blame for four-year-old Steve's lack of interest in his dolls, cars and stuffed (packed) animals. Each morning he tips out three washing baskets of toys all over his floor, listlessly pulls out something and shortly after is standing at his mother's desk or following her into the kitchen saying: "Mummy, I am bored."

    A family therapist (心理医生) explains why children lose interest when they have a whole "toy shop" at home: "According to their brain development, little children are not in a position to judge the quality of a variety of things at once. There is always just one favorite toy for the moment. All the rest is left lying about." What can parents do to stop their children from being oversupplied with toys? Under no conditions simply make something disappear without the child's knowledge. If he/she takes no more notice of a toy, a parent can ask if it can be stored or given away. Be warned though the child will always say he/she wants it then! A talk with relatives and friends may also help. Lyn is the mother of four-year-old Jessie, and we like her way. A small set of shelves in her child's room holds the toys and books that are the current (at present) favorites. When it seems to her that her daughter is tired of these toys, they put them away in a box together and select some other toys from a cupboard in another room. The box of "old" toys goes into the cupboard. When her child says she is "bored", they also get something from her cupboard - it may be something she has had for some time but because she hasn't seen it for a while it is almost like a new toy.

    Some favorite toys stay out all the time, and there is collection of dolls which sits in the corner, but in this way Lyn has found that she has fewer toys to put away at the end of the day and her daughter always has something "fresh" to play with.

    Scientists Diego Kersting and Cristina Linares have found that some coral species are able to recover from harmful warming events through a unique survival strategy (策略)—known as "rejuvenescence" (新生)—among corals in the Mediterranean Sea. The findings represent some rare good news for corals around the world, which are facing numerous severe threats—most notably, climate change.

    "The main threats are climate change, overfishing, pollution and coastal urbanization," Kersting said. "But currently, climate change is probably the one causing the most coral cover declines. Warming stresses corals up to a point that may cause death. Some corals bleach (白化) before dying. Other corals do not bleach but die directly." He went on, "Our findings are significant because this survival strategy was only known from fossil corals that existed hundreds of millions of years ago. It is the first time that it has been found in a living coral. Thanks to our findings, we know now that some corals are able to recover, but unfortunately this is not enough in the current climate change context."

    For their research, Kersting and Linares monitored 243 colonies of the endangered reef-building coral Cladocoracaespitosa in Spain's Columbretes Islands Marine Reserve over 16 years, starting in 2002. The monitoring revealed that Cladocoracaespitosa in the Mediterranean uses rejuvenescence to cope with warming events. This process involves the polyps — or the individual coral animals in a colony—shrinking inward and abandoning their skeletons (骨骼) during warm periods, before rejuvenating at a later point. "What happens is that some polyps in a coral colony—sometimes just one— reduces completely its dimensions and partially retreats from its skeleton," Kersting said. "Once the stressful event is over, the shrunken or rejuvenated polyp recovers its size and builds up a new skeleton. Eventually, it begins to reproduce itself through budding and begins to cover the dead colony surfaces."

    He continued, "The results were very surprising because I started to observe colonies that were dead years ago, that were showing living parts many years after their death."

    Retired jet engines could help clear the smog that smothered big cities.

    To land at Indira Gandhi Airport is to descend from clear skies to brown ones. New Delhi's air is poisonous. According to the World Health Organization, India's capital has the most polluted atmosphere of all the world's big cities. The government is trying to introduce rules that will curb emissions-allowing private cars to be driven only on alternate days, for example, and enforcing better emissions standards for all vehicles.

    But implementing these ideas, even if that can be done successfully, will change things only slowly. A quick fix would help. And Moshe Alamaro, a researcher at the Massachusetts Institute of Technology, thinks he has one. His idea is to take a jet engine, put it next to one of India's dirty coal-fired power plants, point its exhaust nozzle at the sky and then switch it on. His hope is that the jet's exhaust will disrupt a meteorological phenomenon known as "inversion", in which a layer of warm air settles over cooler air, trapping it, and that the rising stream of exhaust will carry off the tiny particles of matter that smog is composed of. Inversion exacerbates air pollution in Delhi and in many other cities, from Los Angeles to Tehran. A particularly intense example caused the Great Smog of London in 1952, when four days of air pollution contributed to 12,000 deaths.

    Dr Alamaro thinks a jet engine could punch through the inversion layer to create a "virtual chimney" which would carry the trapped pollution above it, so that it could be dispersed in the wider atmosphere. He calculates that all the emissions from a gigawatt coal-fired power plant could be lifted away using a single engine with a nozzle speed of 460 metres a second.

    However, he has not calculated whether a jet engine could disrupt the inversion layer and allow the pollution to escape the city-so he is now going to test that hypothesis. Within eight months, Dr Alamaro plans to put one of his updrafters next to a coal-fired power plant and monitor what happens using a fleet of drones. He is in discussions with Tata Group, a conglomerate with an electricity-generating arm, to run it next to one of the firm's power stations.