Children have their own rules in playing games. They seldom need a referee(裁判) and rarely trouble to keep scores. They don't care much about who wins or loses, and it doesn't seem to worry them if the game is not finished. Yet, they like games that depend a lot on luck, so that their personal abilities cannot be directly compared. They also enjoy games that move in stages, in which each stage, the choosing of leaders, the picking-up of sides, or the determining of which side shall start, is almost a game in itself.

    Grown-ups can hardly find children's games exciting, and they often feel puzzled（迷惑的）at why their kids play such simple games again and again. However, it is found that a child plays games for very important reasons. He can be a good player without having to think whether he is a popular person, and he can find himself being a useful partner to someone of whom he is ordinarily afraid. He becomes a leader when it comes to his turn. He can be confident, too, in particular games, that it is his place to give orders, to pretend to be dead, to throw a ball actually at someone, or to kiss someone he has caught.

    It appears to us that when children play a game they imagine a situation under their control. Everyone knows the rules, and more importantly, everyone plays according to the rules. Those rules may be childish, but they make sure that every child has a chance to win.

    Artificial intelligence keeps defeating human, it is making countless victories against human in different fields of life and trying to push human to the corner.

    Google's DeepMind has defeated the world's number one player Ke Jie. Human brain somehow has been replaced by a machine and scientists are working very hard on developing a human brain by implanting a chip and connecting it to the thick neuron that connects the two hemispheres of the brain. Well, who doesn't want to get his brain upgraded to be as smart as the brain of Albert Einstein or Charles Darwin?

    Humans will probably one day invent a brain that can be implanted in the human skull and reprogram all the human thoughts, but this invention doesn't seems to be happening in the foreseeable future since human brain took millions of years to evolve. Some scientists believe that human will defeat death in the next twenty hundred years but they can't really predict how long it's going to take to develop a human brain that can completely replace the natural brain.

    Despite of this accomplishment in the field of artificial intelligence, it couldn't crease people from believing that science can't stand alone. For instance, AI can imitate human brain and most of the time outperforms it, but there are still a lot of hidden secrets. AI outsmarted Ke Jie has consciousness unlike the AI, Ke Jie felt sad when he was defeated and buried his face in his hands but the AI didn't feel happy and celebrate his victory.

    The computer of 1960 is the same as the computer of 2017 in terms of consciousness, there is no signs so far telling us that there is an algorithm(运算)that can make a conscious computer and decipher (译解) its feelings. We can predict what the future will look like according to the past, especially from scientific point of view but the development of human brain seems unpredictable and unknown.

    Forcing waiters and waitresses to survive on tips from customers rather than normal wages is a pointless, crude, and unique American custom that, in the past several years, a handful of progressive restaurant owners have attempted to do away with. Danny Meyer, CEO of Union Square Hospitality Group, is about to join their ranks and has announced that he plans to gradually stop tipping at the company's 13 restaurants.

    What, exactly, is wrong with tipping? As Brian Palmer has explained, more or less it's everything. To start, leaving a waiter's pay in the hands of customers has a feeling of classism (阶级歧视). And in theory, handing restaurant customers the power to tip is at least supposed to motivate better service. This fails in practice because humans turn out to be pretty arbitrary (随意的) about their tipping behavior. Research has shown that the amount diners tip has very little to do with their level of satisfaction. All of this doesn't encourage waiters and waitresses to do anything but turn over as many tables as possible.

    Tipping is also very unfair to kitchen staff. The law allows restaurants to divide tips between front-of-the-house workers like waiters, hosts, hostesses, and bartenders (调酒师), but not cooks. This creates a system in which the people serving the food in a restaurant can earn more than the people preparing it.

    One of the most fascinating parts of Meyer's move is that, unlike some restaurant owners who have taken an anti-tipping stand, he won't simply add a standard extra charge to diners' bills. Rather, Union Square Hospitality Group means to raise menu prices enough to fully cover the cost of a meal. If Meyer manages to move away from tipping at all without hurting his profits, it would almost certainly set the stage for others to follow suit.

    The fridge is considered necessary. It has been so since the 1960s when packaged food list appeared with the label: "Store in the refrigerator."

    In my fridge less Fifties childhood, I was fed well and healthy. The milkman came every day, the grocer, the butcher, the baker, and the ice-cream man delivered two or three times each w eek. The Sunday meat would last until Wednesday and the bread and milk left became all kinds of cakes. Nothing was wasted, and w e w ere never troubled by rotten food. Thirty years on, food deliveries have stopped, and fresh vegetables are almost impossible to get in the country.

    The invention of the fridge contributed comparatively little to the art of food preservation. Many well-tried techniques already existed — natural cooling, drying, smoking, salting, sugaring, bottling...

    What refrigeration did promote was marketing — marketing hardware and electricity, marketing soft drinks, marketing dead bodies of animals around the world in search of a good price.

    Consequently, most of the world's fridges are to be found, not in the tropics where they might prove useful, but in the rich countries with mild temperatures where they are climatically almost unnecessary. Every winter, millions of fridges hum (make a low continuous sound) away continuously, and at vast expense, busily maintaining an artificially-cooled space inside an artificially-heated house —while outside, nature provides the desired temperature free of charge.

    The fridge's effect upon the environment has been clear, while its contribution to human happiness has been unimportant. If you don't believe me, try it yourself, invest in a food cupboard and turn off your fridge next winter. You may miss the hamburgers, but at least you'll get rid of that terrible hum.

    Most people know something about the greenhouse effect. Factories send gasses such as carbon dioxide, or CO₂, into the atmosphere, the air around the earth. In the past, this wasn't a problem because trees absorbed the CO₂. But now people in many countries are cutting down billions of trees all around the world. At the same time, factories are sending more CO₂ into the atmosphere. It's difficult to believe, but factories put billions of tons of CO₂ into the atmosphere every year. One ton is over 2000 pounds, so it is a lot of pollution. There is too much CO₂ and there aren't enough trees, so the world is getting warmer. In other words, we have a greenhouse effect. This is terrible for the environment.

    What can we do about this? Firsts we can stop using so much coal and oil. We can learn to use different kinds of energy: the sun, wind, steam from volcanoes, and heat from inside the earth. Second, instead of cutting down trees, we should plant more trees. One tree can absorb ten pounds of carbon dioxide every year.

    The trees are good for the earth's atmosphere and for Guatemala (拉丁美洲国家危地马拉).In small towns and villages in Guatemala, most women are poor and have hard lives. Trees help them in three ways. First, the Connecticut factories pay them to plant the trees. Their pay is com, not money. The com is good for their children. Second, these women know a lot about their environment. They know where to plant when to plant, and what kinds of trees to plant. For example, they plant many fruit trees. The fruit gives them vitamins for their families^' diets. Other trees are good for firewood. In a few years, the women won't spend so much time looking for firewood. Third, all these trees are good for the soil. Now rain can't wash the soil down from the mountains so easily.

    This plan isn't enough to stop the greenhouse effect. However, it's a start. The woman of Guatemala are helping themselves and helping their environment.