It could happen just about any time you step out in public. You get onto an almost-empty bus, but the next passenger in decides to ignore dozens of empty seats to sit right next to you. While you're waiting in line at a supermarket, the next customer insists on standing only two inches behind you and shouting into his cell-phone. You go into a public restroom, and the next person to enter decides to use the next stall. Transgressions(冒犯) like these don't just make us feel uncomfortable; we often feel anxious, alarmed; and violated(被侵犯的). It is the attack of the personal-space invaders.

    In any society, shared definitions of personal space govern how we interact with other people. People living in densely(密集地) populated cities like Mumbai, Beijing, or Mexico City tend to require less personal space than people living in sparsely(稀少地) populated places within the country. In America, New Yorkers often have smaller requirements than residents of western states, like Montana, Shenandoah and Wyoming. Because everyone has different standards, gestures that are innocent in one place can be interpreted as opposite in another, especially in Britain.

    As the British etiquette(礼仪) website Debrett puts it, as a British person, somebody standing too close may make you "focus less on what somebody is saying than on how close they are to you". Simple acts like putting an arm around someone you don't know may seem friendly in China, but they can make us very uncomfortable. People from many European countries such as France and Spain kiss each other on the cheek when they meet, yet to British person, this seems too friendly and "touch-freely". The website explains! "The British are not backslappers(拍人后背的人) and generally do not show affection in public".

    Are British people unfriendly? Far from it. The website adds that they are not as "stand-offish and aloof' as they may seem, but very friendly and helpful to foreigners. However, remember not to be too close. If you are going to come closer than an arm's length, please let them know.

    We've talked about snails（蜗牛）and their slow move.But much of the time snails don't move at all.They're in their shells（壳）—sleeping.

    Hot sun will dry out a snail's body.So at the least sign of hot sun,a snail draws its body into its shell and closes the opening with a thin cover.Then it goes to sleep.A snail will die in a heavy rain.So whenever it rains,it goes inside its shell house and goes to sleep.A snail can sleep for as long as it needs to.It can take a short sleep.Or it can sleep for days at a time.And it spends all the winter months in its shell,asleep.

    the shell.When hungry,the snail looks for food.It can't see very well.Its eyes,at the ends of the top feelers（触角）are very weak.But its sense of smell is very strong.It helps the snail to the new greens.Then the snail's little mouth goes to work.

    A snail's mouth is no longer than the point of a pin（针）.Yet it has 256,000 teeth!The teeth are so small that you can't see them.But they do their work.If you put a snail in a hard paper box,it will eat its way out.And if a snail wears out its teeth,it will grow new ones.

    Mostly,a snail looks for food at night.But on cloudy days it eats in the day time.It cats all day long.A snail can go on eating for hours and never feel full.

                                                                     The Diet Zone: A Dangerous Place

    Diet Coke, diet Pepsi, diet pills, no-fat diet, vegetable diet… We are surrounded by the word “diet” everywhere we look and listen. We have so easily been attracted by the promise and potential of diet products that we have stopped thinking about what diet products are doing to us. We are paying for products that harm us psychologically and physically.

    Diet products significantly weaken us psychologically. On one level, we are not allowing our brain to admit that our weight problems lie not in actually losing the weight, but in controlling the consumption of fatty, high-calorie, unhealthy foods. Diet products allow us to jump over the thinking stage and go straight for the scale(秤)instead. All we have to do is to swallow or recognize the word “diet” in food labels.

    On another level, diet products have greater psychological effects. Every time we have a zero-calorie drink, we are telling ourselves without our awareness that we don't have to work to get results. Diet products make people believe that gain comes without pain, and that life can be without resistance and struggle.

    The danger of diet products lies not only in the psychological effects they have on us, but also in the physical harm that they cause. Diet foods can indirectly harm our bodies because consuming them instead of healthy foods means we are preventing our bodies from having basic nutrients. Diet foods and diet pills contain zero calorie only because the diet industry has created chemicals to produce these wonder products. Diet products may not be nutritional, and the chemicals that go into diet products are potentially dangerous.

    Now that we are aware of the effects that diet products have on us, it is time to seriously think about buying them. Losing weight lies in the power of minds, not in the power of chemicals. Once we realize this, we will be much better able to resist diet products, and therefore prevent the psychological and physical harm that comes from using them.

    It was dangerously cold. A few drivers slipping and sliding off the road and back on again had cut deep ruts（车辙）in the mud. And the ruts became frozen solid. The drum of our truck's aging engine worried us.

    Trees and bushes heavy with snow bent to form an icy tunnel. We inched along the scary route as Howard grasped the steering wheel（方向盘）tightly, trying to keep the truck in the ruts. We were now riding through a nightmare with no going back. I kept praying the truck would not quit.

    However, the engine's coughing grew worse. We came to a bumping stop. Hot tears ran down my face. We noticed a small house off in the distance. “I will go for help.” Howard's words ruined my common sense and panic took over. We would take the children — we would walk to that house together!

    But the snow was deep, and our two children, asleep in the cab, were too heavy to carry. My husband convinced me to let him go alone. If no one was home or they didn't answer the door, he would come back and we'd try to hike out to a main road. For now, it was safer in the truck. I wish I could say I have faith, but when he walked away, I was mad at the world.

    It seemed as if hours had passed before I heard a familiar voice and a kind laugh of another man as they approached in the snow. The older fellow invited us to go up to the house where his wife was waiting. Two wide-awake kids moved across the seat, ready for adventure. Their voices and laughter carried in the cold night air. When we finally got close, a cheerful woman opened the door. Warm air and the smell of hot buttered popcorn and chocolate drew us in.

     Relieved, my prayers were heard!

    Navarathri, which is celebrated throughout India, falls in September or October. On the first three days, people pray (祈祷) to the goddess Durga, the protector who destroys all evil. The next three days they pray to Lakshmi, the goddess of wealth. Then, also for three days, they look to Saraswathi, the goddess of wisdom and knowledge. The tenth and final day of the festival is for the goddess Durga. On this day many years ago, Durga killed the evil buffalo-headed monster, Mahishasura.

    My daughter and I took out the models of the gods and goddesses that we had stored away last year. Soon the room was littered with all kinds of dolls. We usually buy at least one new doll every year. On the tenth day, the dolls are carefully put away. If a doll is too damaged to be shown, it is never thrown away. Instead, it is put deep into the seas.

    In our hallway six long wooden steps are set up. First, we spread a thick white cloth over the steps. Now it's time to put the dolls on the steps carefully. Every year, the gollu is different. Sometimes — as the collection grows — there is no space to fit all of the dolls on the steps. Smaller dolls can also be placed on the floor.

    Every night there are prayers, music, dancing, and a large meal for many people. In northern India, the children sing songs while doing the dandiya raas, a traditional dance. Every dancer also has two wooden sticks — called dandiya — that he or she uses to make a sound in time to the lovely music. Dancing the dandiya raas helps people think of the true meaning of Navarathri — togetherness, laughter, and fun!

    In 1800, only three percent of the world's population lived in cities. Only one city — Beijing — had a population of over a million. Most people lived in rural areas, and never saw a city in their lives. In 1900, just a hundred years later, roughly 150 million people lived in cities, and the world's ten largest cities all had populations exceeding one million. By 2000, the number of city dwellers exceeded three billion; and in 2008, the world's population crossed a tipping point — more than half of the people on Earth lived in cities. By 2050, that could increase to over two-thirds. Clearly, humans have become an urban species.

    In the 19th and early 20th centuries, many people viewed cities negatively — crowded, dirty environments full of disease and crime. They feared that as cities got bigger, living conditions would worsen. In recent decades, however, attitudes have changed. Many experts now think urbanization (城市化) is good news, offering solutions to the problems of Earth's growing population.

    Harvard economist Edward Glaeser, author of The Victory of the Cir, is one such person. Glaeser argues that cities are very productive because "the absence of space between people" reduces the cost of transporting goods, people, and ideas. While the flow of goods has always been important to cities, what is most important today is the flow of ideas. Successful cities enable people to learn from each other easily, and attract and reward smart people with higher wages.

    Another urbanization supporter is environmentalist Stewart Brand. Brand believes cities help the environment because they allow haft of the world's population to live on about four percent of the land. This leaves more space for open country, such as farmland. City dwellers also have less impact per person on the environment than people in the countryside. Their roads, sewers, and power lines need fewer resources to build and operate. City apartments require less energy to heat, cool, and light. Most importantly, people in cities drive less so they produce fewer greenhouse gases per person.

    So it's a mistake to see urbanization as evil; it's a natural part of development  The challenge is how to manage the growth.