题目

阅读理解 Over the past half-century, scientists have settled on two reasonable theories related to baby talk. One states that a young child's brain needs time to master language. The second theory states that a child's vocabulary level is the key factor. According to this theory, some key steps have to occur in a logical sequence before sentence formation occurs. In 2007, researchers at Harvard University, who were studying the two theories, found a clever way to test them. More than 20,000 internationally adopted children enter the U.S. each year. Many of them no longer hear their birth language after they arrive, and they must learn English more or less the same way infants(婴儿) do. International adoptees don't take classes or use a dictionary when they are learning their new tongue. All of these factors make them an ideal population in which researchers could test these competing theories about how language is learned. Neuroscientists Jesse Snedeker, Joy Geren and Carissa Shafto studied the language development of 27 children adopted from India between the ages of two and five years. These children began learning English at an older age than US natives and had more mature brains. Even so, just as American-born infants, their first English sentences consisted of single words. The adoptees then went through the same stages as typical American-born children, though at a faster clip. The adoptees and native children started combining words in sentences when their vocabulary reached the same sizes, further suggesting that what matters is not how old you are or how mature your brain is, but the number of words you know. This finding—that having more mature brains did not help the adoptees avoid the baby talk stage—suggests that babies speak in baby talk not because they have baby brains, but because they have only just started learning and need time to gain enough vocabulary. Before long, the one-word stage will give way to the two-word stage and so on. Learning how to chat like an adult is a gradual process. But this finding also raises an even older and more difficult question. Adult immigrants who learn a second language rarely achieve the same proficiency in a foreign language as the average child raised as a native speaker. Researchers have long suspected there is a "critical period" for language development, after which it cannot proceed with full success to fluency. Yet we still do not understand this critical period or know why it ends. （1） What is the writer's main purpose in Paragraph 2? A . To argue that culture affects the way children learn a language. B . To give reasons why adopted children were used in the study. C . To reject the view that adopted children need two languages. D . To justify a particular approach to language learning. （2） What does the Harvard finding show? A . Language learning takes place in ordered steps. B . Some children need more conversation than others. C . Children with more mature brains skip baby talk stage. D . Vocabulary makes little difference to sentence formation. （3） When the writer says "critical period", he means a period when_______. A . children start to learn a second language B . immigrants want to learn another language C . adults need to be taught by native speakers D . language learners may achieve native-like fluency （4） What does this passage mainly talk about? A . What is baby talk. B . Why babies learn a second language easily. C . What affects children's language development. D . How children expand their vocabulary gradually. 答案： B A D C

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