Some children are backward in speaking. Most often the reason for this is that the mot

her is insensitive to the cues and signals of the infant, whose brain is programmed to mop up(吸收) language rapidly. There are critical times, it seems, when children learn more readily. If these sensitive periods are neglected, the ideal time for acquiring skills passes and they might never be learned so easily again. A bird learns to sing and to fly rapidly at the right time, but the process is slow and hard once the critical stage has passed.Linguists suggest that speech milestones are reached in a fixed sequence and at a constant age, but there are cases where speech has started late in a child who eventually turns out to be of high IQ (Intelligence Quotient(智商. At twelve weeks a baby smiles and utters vowel-like sounds; at twelve months he can speak simple words and under- stand simple commands; at eighteen months he has a vocabulary of thirty to fifty words. At three he knows about 1000 words which he can put into sentences, and at four his language differs from that of his parents in style. rather than grammar.Recent evidence suggests that an infant is born with the capacity to speak. What is special about man's brain, compared with that for the monkey, is the complex system which enables a child to connect the sight and feel of, say, a teddy-bear with the sound pattern "teddy-bear". And even more incredible(不可思议) is the young brain's ability to pick out an order in language from the hubbub(喧哗) of sound around him, to analyse, to combine and recombine the parts of a language in novel ways.But speech has to be triggered(触发), and this depends on interaction between the mother and the child, where the mother recognizes the cues and signals in the child's babbling, (咿咿呀呀) clinging, grasping, crying, 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 cues is essential to the growth and development of language.

1.The reason some children are backward in speaking today is that ____.

A、they do not listen carefully to their mothers

B、their brains have to absorb too much language at once

C、their mothers do not respond to their attempts to speak

D、their mothers are not intelligent enough to help them

2.By "critical times" the author means ____.

A、difficult periods in the child's life

B、moments when the child becomes critical towards its mother

C、important stages in the child's development

D、times when mothers often neglect their children

3.Which of the following is NOT implied in the passage____.

A、The faculty of speech is inborn in man.