[originaltext]Play is the principal business of children, and more and more in

Play is the principal business of children, and more and more in recent years researches have shown the great importance of play in the development of a human being. From earliest infancy, every child needs an opportunity and the right materials for play, and the main tools of play are toys. Their main function is to suggest, encourage and assist play. Therefore it is important to choose suitable toys for different stages of a child’s development. Some research in recent years on infant development has shown the standard a child is likely to reach, within the range of his inherited abilities, is largely determined in the first three years of his life. So a baby’s ability to profit from the right play materials should not be underestimated. A baby who is encouraged and stimulated, talked to and shown things and played with, has the best chance of growing up successfully. The next stage, from three to five years old, curiosity knows no bounds. Every type of suitable toy should be made available to the child, for trying out, experimenting and learning, for discovering his own particular ability—bricks and construction toys， painting and making things, sand and water play, toys for imaginative and pretending play, the first social games for learning to play and getting on with others. By the third stage of play development—from five to seven or eight years—the child is at school. But for a few more years play is still the best way of learning, at home or at school. It is easier now to see which type of toys the child most enjoys.
12. What is the main function of toys?
13. Why is it said the first three years of one’s life is important?
14. What do children at ages three to five like doing?
15. What does the passage mainly discuss?