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Article: "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  . 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... Question: Some birds have their own territorial systems so that   _  . Yes or no, is the answer "they don't need to fight or chase each other"?
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Yes


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Article: A scientist who developed a way to calculate how much water is used in the production of anything from a cup of coffee to a hamburger was awarded the 2008 Stockholm Water Prize. Professor John Anthony Allan of the University of London in Britain won the award for introducing the idea of "virtual water  ", a calculation method that has changed the nature of trade policy and research. Allan has written seven books and published more than 100 papers. The Stockholm International Water Institute said this idea is now embedded   in the production of foods and industrial products. The institute said Allan's work had made a big effect on global trade policy and research, especially in water-scarce   regions. "The improved understanding of trade and water management issues on local, regional and global scales are of the highest value for the successful and sustainable   use of water resources," it said. "People do not only use water when they drink it or take a shower," the institute said. "Behind the morning cup of coffee, there are 140 liters of water that was used to grow, produce, package and ship the beans." That is about as much water as a person in England uses on average for all daily drinking and household needs. "For a single hamburger, about 2,400 liters of water are needed. In the USA, the average person uses nearly 7,000 liters of virtual water every day." It said that was more than three times the average use of a Chinese person. Question: Allan was awarded the prize because   _  . Yes or no, is the answer "he came up with the idea of virtual water"?
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Article: Maupassant(*)was born in 1850 in northern France. His early life was not happy. His parents separated when he was 11. Most of his education came informally from Gustave Flaubert--his mother's friend and his godfather, a journalist and novelist. Often Flaubert would let him take a walk and then ask him to write 100 lines about what he saw. This type of training developed in Maupassant a sense of observation, which he later put to use in his writing. Flaubert also allowed Maupassant to attend his Sunday gatherings with others in his literary circle For a few years, Maupassant was connected with the Ministry of Public Instruction. It is interesting to note that Monsieur Loisel, a poor man character in The Necklace, worked there. He also served in the French army during the Franco-Prussian War. His favorite writing subjects were peasants, servants, in the city, and the Francd-Prussian War. At an early age, Maupassant started writing short stories. In 1880, some of his works were published and he received a wide reputation for Boule de Suif (Ball of Tallow). With this success, he began to work full-time on writing. During the next ten years, he wrote over 300 stories, including six novels, three travel books, and a book of verse. Through them, he earn a lot of money. His writing was classical and simple, avoiding social comments and dirty details. His works often showed a real world and an accurate knowledge of the subject. Although Maupassant wrote in many forms, he received widest recognition for his short stories. By 1890, Maupassant was suffering from the latter staged of syphilis . He died in 1893 in Paris. Question: What are the characteristics of Maupassant's stories? Yes or no, is the answer "They have few social comments."?
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