Although each baby has an individual schedule of development, general patterns of growth have been observed Three periods of development have been identified, including early infancy, which 1from the first to the sixth month middle infancy, from the sixth to the ninth month and late infancy, from the ninth to the fifteenth month. Whereas the newborn is 2with his or her inner world and responds 3to hunger and pain in early infancy, the baby is already aware of the surrounding world. During the second month, many infants are aware more and can raise their heads to look at things. They also begin to smile at people. By four months, the baby is 4for things but not yet grasping them in its hands. It is also beginning to be 5to strangers and may scream when a visiting 6tries to pick it up. By five months, the baby is 7objects and putting them into his mouth. Some babies are trying to 8themselves with their hands. In middle infancy, the baby 9on practicing a great many speech sounds. It loves to imitate actions and examine interesting objects. At about seven months, it begins to crawl, a skill that it masters at the end of middle infancy. In late infancy, the baby takes an interest in games, songs and even book. 10toward walking moves through standing, balancing, bounding in place, and walking with others. As soon as the baby walks well alone, it has passed from infancy into the active toddler (学步儿童) age. A. searching B. Progress C. feed D. extends E. Appeal F. concentrates G. amazingly H. grabbing I. relative J. concerned K. indifferent L. alert M. primarily N. meanwhile O. previous