“Keep out or I'll chase you out! This is my property!” You hear this every spring. It is a long musical sound —a bird song! Birds use their songs to communicate different messages to one another. People who study bird sounds are learning their meanings.

    Usually it is the male that sings. Early in spring he sings to say that he has picked out a piece of property. He sings to attract a female of his same kind. Together they will raise a family in his territory (领地). He sings to tell all other birds of his kind to keep out.

    Each kind of bird has its own type of song. Cardinals sing something that sounds a little like “What cheer, cheer, cheer.” Towhees sing, “Drink your tea.”

    Most of the time, birds pay attention only to the songs of birds of their own kind. Cardinals answer cardinals, and song sparrows answer song sparrows. A cardinal knows that a song sparrow will not try to steal its mate. So you can see one reason why a cardinal may chase away another cardinal but will not bother a song sparrow.

    Most different kinds of birds eat different things. To find enough to eat, a bird needs a big piece of land to search in. Many kinds of birds have some ways of dividing up the land into territories. Song sparrows, cardinals ovenbirds, and white-throated sparrows are some of the birds that have territorial systems.

    Especially in early spring, birds work out the boundaries between their territories by singing “keep out” threats and by chasing and fighting each other. The birds continue singing to tell females that they have set up territories. Neighboring birds seem to agree that there are make believe fences between their pieces of property. Then they do not have to waste energy chasing each other instead of taking care of their young.

    Scientists guessed that some birds could recognize their neighbors by small differences in their songs. Two scientists who studied white-throated sparrows found that these birds can even tell the difference between songs of individual birds of their own kind. White-throated sparrows have songs that seem to say “I'm your neighbor” or “I'm a stranger” or “I'm your neighbor to the west.” Other kinds of birds could tell neighbors from strangers by their songs, too.

    Written in the first chapter of the book Pride and Prejudice is an extraordinary sentence of which even a person who has had only a brief look upon the book will not fail to receive a deep impression — It is a truth universally acknowledged that a single man in possession of a good fortune must be in want of a wife. In terms of Sherlock Holmes, we'd better alter the sentence into “It is a fact universally accepted by readers throughout the world that an excellent book in possession of our famous detective Sherlock Holmes is undoubtedly a masterpiece of all times.” Perhaps this is one of the most obvious explanations for the unrivaled popularity of “Holmes series” in the field of detective stories. Overwhelmed by the recommendations provided by my friends, I decided to take a look on this Sherlock Holmes and the Duke's Son originally published by Oxford University Press.

    As a whole, this book is about a case concerning the Duke's missing son. Arthur, the Duke's son, was found out in a certain morning to have disappeared, accompanied with which was also the disappearance of the German teacher. The school master Dr. Huxtable then turned to the famous detective of the time Sherlock Holmes for help. Realizing how tough and important the case is, Holmes immediately made up his mind to accept the case and followed Dr. Huxtable back to Mackleton by train. Having formed a rough idea about the whole matter, Holmes probed into the case immediately and had a careful investigation of the entire area shortly after the arrival, during the process of which he discovered the body of the German teacher Heidegger. Finally, primarily due to his prominent ability as a detective, he managed to unravel the mystery.

    Having once started reading this fiction, I was completely immersed in the mysterious story. At the beginning, unlike other detective stories, this story first delineates the client's strange behavior at length to indicate the severity of the incident in order to attract the readers to continue reading it. As is known to all, vivid depiction is essential to detective stories as it makes the story more authentic and attractive. Therefore, trying to present a “real world” to his readership, Sir Arthur Conan Doyle, author of the original “Holmes series”, has skillfully arranged the plots of the whole story from the perspective of Dr. Watson, a friend of Homes'. In this way, he elaborately (精心)depicted every scene and character in the book. Apart from the special start, the ending of the whole story, being dramatic but reasonable, is certainly an outstanding one. After all, except the author himself, who knows that the Duke's seemingly ordinary secretary is in fact the Duke's bastard(私生子)? In addition, who knows that the Duke actually has already been acquainted with the whole thing before Holmes solves this complicated problem? Yet, surprising as it is, this ending seems so natural that it fits all the plots of the story perfectly well. Closing my eyes, I can even “see” the story happening just like watching a film.

    As far as I am concerned, nothing is more admirable and surprising in the hero Sherlock Homes than his profound knowledge which has certainly assisted him a lot when he was studying the case. Take the bicycle tyres for instance, Holmes is capable of recognizing 42 different varieties of bicycle tyres. Except for his illimitable knowledge, Holmes also specializes in arranging the facts in order and then finding the fact leading him to a great discovery or even the truth itself. In this case, after getting rid of unrelated facts, Sherlock Homes eventually grasped the clue and discovered the amazing fact.

    Needless to say, as a world-renowned masterpiece, Sherlock Holmes and the Duke's Son has attracted and is still charming numerous readers from all corners of the world and people from all walks of life. The “Holmes series” has already set up a standard against which all the following detective fictions are measured. Sherlock Holmes, beyond all doubt, has been a name firmly rooted in people's memories. Although Dr. Watson's closing The Case Book of Sherlock Holmes in 1927 was a great pity to the readers, the discontinuance of the entire “Holmes series” may have actually added to the legendary stature of Sherlock Holmes.

    Grey clouds move as low as smoke over the treetops at Lolo Pass. The ground is white. The day is June 10.It has been snowing for the past four days in the Bitterroot Mountains.Wayne Fairchild is getting worried about our trek over the Lolo Trail-95 miles from Lolo Montana to Weippe in Idaho, across the roughest country in the West. Lewis and Clark were nearly defeated 200 years ago by snowstorms on the Lolo. Today Fairchild is nervously checking the weather reports. He has agreed to take me across the toughest, middle section of the trail.

    When Lewis climbed on top of Lemhi Pass,140 miles south of Missoula, on Aug.12,1805,he was astonished by what was in front of him; "high mountain chains still to the West of us with their tops partially covered with snow.＂Nobody in what was then the US knew the Rocky Mountains existed, with peaks twice as high as anything in the Appalachians back East.

    Today their pathway through those mountains holds more attraction than any other ground over which they traveled, for its raw wilderness is an evidence to the character of two cultures:the explorers who braved its hardships and the Native Americans who prize and conserve the path as a sacred (神圣的)gift. It remains today the same condition as when Lewis and Clark walked it.

    The Lolo is passable only from July to mid-September. Our luck is holding with the weather, although the snow keeps getting deeper. As we climb to Indian Post Office, the highest point on the trail at 7,033 ft, we have covered 13 miles in soft snow, and we hardly have enough energy to make dinner. After a meal of chicken, I sit on a rock on top of the ridge .There is no light visible in any direction, not even another campfire. For four days we do not see another human being. We are occupied with the things that mix fear with joy. In our imagination we have finally caught up with Lewis and Clark.

    The world's first robot police officer has started working. Its name is 'RoboCop' and it went into service for the Dubai Police earlier this week. Robocop's first official duty was to greet guests at the opening of a security conference in Dubai. Apart from greeting visitors' its job was to answer questions and give directions. RoboCop has a built — in tablet for people to interact with. People can use the tablet to pay traffic fines and use other smart police services. The tablet is linked to a police station, so people can talk to human police officers. In addition, RoboCop can speak six languages, including English and Arabic. The 170 - centimetre - tall robot can also shake hands, salute people and recognize people's emotions and facial expressions.

    Dubai Police says RoboCop is the first of many robot police officers for the city. A spokesman said that by 2030, 25 per cent of the Dubai Police force will be robots. He said: “We are looking to make everything smart in Dubai Police. By 2030, we will have the first smart police station which won't require human employees.”

    “The RoboCop is the latest smart addition to the police force and has been designed to help us fight crime, keep the city safe and improve happiness levels,” He added. He also said that RoboCop would, “assist and help people in the malls or on the streets”. An official at the security conference commented that the future is here now, saying: “The age of the robots is no longer coming. It has arrived.”

    The Nobel Prize Winners in Literature

    Rabindranath Tagore(1913)

    Prize motivation: because of his deep sensitive, fresh and beautiful poetry, with perfect skills, he has made his poetic thought, expressed in his own English words，part of the literature of the West.

    William Faulkner (1949)

    Prize motivation: for his powerful and artistically unique contribution to the modern American novel.

    Ernest Miller Hemingway(1954)

    Prize motivation：for his mastery of the art of narrative, most recently demonstrated in The Old Man and the Sea.

    John Steinbeck (1962)

    Prize motivation: for his realistic and imaginative writings, combining sympathetic humour and keen social perception.

    Sir Winston Leonard Spencer Churchill(1953)

    Prize motivation：for his mastery of historical and biographical description as well as for his brilliant speech skills in defending noble human values.

    Claude Simon (1985)

    Prize motivation: he in his novel combines the poet's and the painter's creativeness with a deepened awareness of time in the description of the human condition.

    Mo Yan (2012)

    Prize motivation：he, with dreamlike realism，combines folk tales，history and the contemporary.

    Bob Dylan (2016)

    Prize motivation：for having created new poetic expressions within the great American song tradition.

    Elephants are able to know the difference between a man and a woman, and can tell an adult (成年人) from a child—all from the sound of a human voice. This is according to a study in which researchers played voice recordings to wild African elephants.

    The animals showed more fear when they heard the voices of adult Masai men. Usually Masai people hunt elephants, and this suggests that animals have grown to listen for and avoid them.

    Prof. Karen McComb and Dr Graeme Shannon from the University of Sussex led the study. They explained that in former research they had used similar experiments to show that elephants could tell—from the sound of a lion—whether the animal was a female (雌性) or a more dangerous male (雄性).

    Prof  McComb wanted to find out if the animals used their very sharp sense of hearing to recognize danger from humans.

    The scientists recorded Masai men, women and children saying, in their own language, "Look, look over there, a group of elephants are coming." They also recorded Kamba men saying this phrase.

    Masai people often come across elephants, which can result in violent (暴力的) hunting. Kamba people, however, mainly feed on agriculture, which does not generally bring them into violent touch with the animals.

    When the team played recordings of these different voices through a hidden speaker, they found that elephant family groups showed more fear in response to the voice of a Masai man, than to a Kamba man's voice. And the adult male Masai voices caused far more violent response than the voices of women or boys.