Scientists found that sleeping considerably improves our creativity. After taking a nap people are able to think faster and put more imagination into their thinking. Besides, if we dream, the thinking abilities are improved even more.
    Researchers consider that sleeping on a problem in most cases leads to elucidation(解释). They say when a person enters a phase called Rapid Eye Movement (REM) during sleep, it increases the effect. Such phase takes place right before we awake and according to scientists it helps our brain make links between unrelated subjects.
    In the study, led by Professor Sara Mednick, scientists made a conclusion that the REM was "important for assimilating(消化) new information into past experience" in order to find solutions to creative problems.
    Prof. Mednick is a psychiatrist at the University of California. Her study involved the analysis of 77 adults. Each participant was given several word-associated creative tasks. All tasks were given in the morning, with participants being shown a number of groups of 3 words, for example: cookie, heart and sixteen. They were asked to come up with a word that would be associated with all three given terms—like sweet. Sometime later, after some participants were allowed to sleep, they were asked to perform the same tasks and some new ones. It is worth mentioning that while some people slept, researchers used brain scans to see the type of sleep each participant entered.
    When given the same tasks, participants, who took a nap, were able to give more varied solutions, some of which were much better than they gave earlier. But when given new tasks, researchers found that those who entered REM sleep had a 40 percent better result compared to the performance they showed in the morning.
    The United States is a country of immigrants. It is a place where people from all over the world come to build a better life. Some immigrants bring their families. Some bring a few of their favorite things. Others come alone with nothing but determination. One thing that every immigrant brings with them is their culture.
    American immigration began in 1607 with the colony (殖民地) of Jamestown. In 1620, another group of people left England to build a settlement in America. They wanted to go to a place where they could practice their religion freely. Then many more people left their homes in Europe to build a better life in America. Many also came to America from Africa. By 1770, more than two million people had moved to America. Later on, more people came to the United States than ever before.
    In cities all over America, you can see different cultures that formed this country. Many things that you may think of as being “American” are actually from a foreign culture. Some of the best examples of this are the foods people eat. Pizza and spaghetti are foods that all Americans know and love. But both of them are from Italy. Baseball is an all-American sport. But the hot dogs that people eat during the game are a type of food that was brought to America by German immigrants.
    Over time, pizza and hot dogs have become a part of what is considered to be American food. In the same way, different groups of people have come together to define what an American is. An American can be a person of any background. An American can be of any faith. An American can be of any skin color. They can speak English clearly. They can speak English with an accent. Each new immigrant adds something new to American culture. It will keep changing as more people come to this country.
    I'm part of the Roots & Shoots program founded by Dr. Jane Goodall. The program is intended to make and promote positive changes in the world. As Dr. Goodall says, “What you do makes a difference, and you have to decide what kind of difference you want to make.”
    In Bulgaria, where I live, homeless dogs are everywhere. Many people here turn a blind eye to them. But I cannot ignore the life of a street dog whenever I see one wandering in the street, looking for something to eat. That's why I'm no longer a food waster. When I see wasted food, I always think of a hungry dog climbing to garbage bins, searching for food that people have thrown there. When eating in a restaurant, I'm not afraid to take leftover food to feed stray cats or dogs.
    A week ago, I saw a homeless dog around the garbage bins. Immediately I knelt down, spoke to her softly and ran my hands over her. I could see that she had had puppies. I couldn't imagine how she could have been able to care for them. Hours earlier, I'd bagged up a plate of leftover fish. As I unwrapped it, she wagged her tail and sniffed at it. She ate all the fish in no time.
    It's sad, isn't it? I can't understand why many of us waste so much and think little of it. These homeless animals have taught me that food is precious. Even when I don't have leftovers with me, I'll take the time to get something from the grocery store to feed them.
    I know my power is small, so I hope that next time you see wasted food, do turn it into worthy food. You have the power to save a life!
    The world itself is becoming much smaller by using modern traffic and modern communication means. Life today is much easier than it was hundreds of years ago, but it has brought new problems. One of the biggest is pollution. To pollute means to make things dirty. Pollution comes in many ways. We see it, smell it, drink it and even hear it.
    Man has been polluting the earth. The more people, the more pollution. Many years ago, the problem was not so serious because there were not so many people. When the land was used up or the river was dirty in one place, man moved to another place. But this is no longer true. Man is now slowly polluting the whole world.
    Air pollution is still the most serious. It's bad for all living things in the world, but it is not the only one kind of pollution. Water pollution kills our fish and pollutes our drinking water. Noise pollution makes us angry more easily.
    Many countries are making rules to fight pollution. They stop people from burning coal in houses and factories in the city, and from putting dirty smoke into the air.
    Pollution by carbon dioxide is now the most dangerous kind of air pollution. It is caused by heavy traffic. It is true that if there are fewer people driving, there will be less air pollution.
    The earth is our home. We must take care of it. That means keeping the land, water and air clean. And we must take care of the rise in population at the same time.
    While beach vacations may be a great way to take your mind off work,lakes surrounded by mountains make for an even grander experience.If you are looking for some peace on your vacation,we have some recommendations for you in the Caucasus(高加索).
Lake Sevan
    Lake Sevan is situated in the central part of Armenia,in the Gegharkunik province.It is the largest lake in Armenia,located 6,200ft above sea level.Along the lake shore,there are various accommodations such as resorts and hotels with plenty of activities to partake in such as windsurfing,swimming and sunbathing.While there,do not forget to visit one of the famous cultural monuments,the Sevanavank Monastery,and it offers a great view of the lake as well.
Lake Paravani
    Lake Paravani,located at 6,801ft above sea level,is in the south of Georgia,near the Javakheti plateau.At this level,altitude sickness can occur and it is a good idea to be prepared to adapt to it properly,or bring medication for altitude sickness.Being a volcanic lake makes for a more interesting experience.The lake is best known for fishing.Do not come home during the winter months when the lake freezes.
Lake Cildir
    Lake Cildir is located in the Ardahan province,East Turkey,near the borders of Georgia and Armenia.It is the second largest freshwater lake of Eastern Turkey,and many tourists are not aware of this beautiful attraction.Lake Cildir is surrounded by mountains of the Caucasus.The lake freezes during late November.If the winter is not extremely cold,you can try some lake activities like ice skating and ice fishing.
Lake Van
    Lake Van is the must visit of all lakes in this list.The largest lake in Turkey,Lake Van is located on the eastern shore of Turkey and is also the most accessible lake here.It's situated at 5,380ft above sea level,and unique to lakes around the world,the water is high in salt content.
阅读理解When milk arrived on the doorstep
    When I was a boy growing up in New Jersey in the 1960s, we had a milkman delivering milk to our doorstep. His name was Mr. Basille. He wore a white cap and drove a white truck. As a 5-year-old boy, I couldn't take my eyes off the coin changer fixed to his belt. He noticed this one day during a delivery and gave me a quarter out of his coin changer.
    Of course, he delivered more than milk. There was cheese, eggs and so on. If we needed to change our order, my mother would pen a note-“Please add a bottle of buttermilk next delivery”-and place it in the box along with the empty bottles. And then, the buttermilk would magically appear.
    All of this was about more than convenience. There existed a close relationship between families and their milkmen. Mr. Basille even had a key to our house, for those times when it was so cold outside that we put the box indoors, so that the milk wouldn't freeze. And I remember Mr. Basille from time to time taking a break at our kitchen table, having a cup of tea and telling stories about his delivery.
    There is sadly no home milk delivery today. Big companies allowed the production of cheaper milk, thus making it difficult for milkmen to compete. Besides, milk is for sale everywhere, and it may just not have been practical to have a delivery service.
    Recently, an old milk box in the countryside I saw brought back my childhood memories. I took it home and planted it on the back porch (门廊). Every so often my son's friends will ask what it is. So I start telling stories of my boyhood, and of the milkman who brought us friendship along with his milk.