A、By crying for others’ attention. B、By pleasing others with smile. C、By asking for food and others. D、By making noise for care.

(16)The first three years of a child’s life is the most intensive period of language and speech development. This is the time when the brain is developing. Language and communication skills are believed to develop best in an environment that is rich with sounds and sights. Also, the child should repeatedly hear the speech and language of other people.(17)The National Institutes of Health says evidence suggests there are important periods of speech and language development in children. This means the brain is best able to learn a language during this period. Officials say the ability to learn a language will be more difficult if these periods pass without early contact with a language.(18)The first signs of communication happen during the first few days of life when a baby learns that crying will bring food and attention. Research shows that most children recognize the general sounds of their native language by six months of age. At that time, a baby also usually begins to make sounds. These sounds become a kind of nonsense speech over time. A long-term American study shows the effect of early education on future learning abilities.(19)It found that children who received higher quality care before starting school had better language skills by those ages than children who had lower quality care. Child care included any care provided by people other than the child’s mother that lasted at least ten hours a week. This included any care given by fathers or other family members.
16. What does the speaker say about a child s first three years?
17. What does the National Institutes of Health tell us?
18. How do babies communicate with others in the few days after birth?
19. What does the American study find?