Recent evidence suggests that an infant is born with the capacity to speak. What is special about man’s brain, compared with that of the monkey, is the complex system which enables a child to connect the sight and feel of, say, a toy-bear with the sound pattern "toy-bear". And even more incredible is the young brain’s ability to pick out an order in language from the mixture of sound around him, to analyse, to combine and recombine the parts of a language in new ways.

　　But speech has to be induced, and this depends on interaction between the mother and the child , where the mother recognizes the signals in the child’ s babbling (咿呀学语) , grasping and smiling, and responds to them. Insensitivity of the mother to these signals dulls the interaction because the child gets discouraged and sends out only the obvious signals. Sensitivity to the child’s non-verbal signals is essential to the growth and development of language.

　　31. The purpose of Frederick II’s experiment was__

　　[A] to prove that children are born with the ability to speak

　　[B] to discover what language a child would speak without hearing any human speech

　　[C] to find out what role careful nursing would play in teaching a child to speak

　　[D] to prove that a child could be damaged without learning a language

　　32. The reason some children are backward in speaking is most probably that__