题目内容：

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Man has a big brain. He can think, learn and speak.        1.   . They know now that dogs, rats and birds can learn, too. They are beginning to understand that men are different from animals because they can speak.

Animals can’t speak.    2. .Apes（猿） can understand some things more quickly than humans, and one or two of them have even learnt a few words.    3.  . They can’t think like us because they have no language. Language is a wonderful thing. Man has been able to build a modern world because he has language.  4.     . How do children learn it? Scientists do not really know. What happens inside our body when we speak? They only know that man can speak because he has a brain.

A. Almost every child can speak his own language very well when he is four or five but no animal learns to speak.

B. But they can’t join words to make sentences.

C. They make noises when they are afraid, or angry, or unhappy.

D. Scientist once thought that men are different from animals because they can think and learn.

A. Almost every child can speak his own language very well when he is four or five but no animal learns to speak. B. But they can’t join words to make sentences. C. They make noises when they are afraid, or angry, or unhappy. D. Scientist once thought that men are different from animals because they can think and learn.