請依下文回答第 16 題至第 20 題
        At certain times in life, we all face changes that many social scientists consider to be natural stages. Takea newborn, William, as an example. The first few months of his life __16__   in a limited environment. In fact,he won’t develop an awareness of his surroundings or truly enter the world __17__    he’s begun to walk andtalk. William will be spending the next few years discovering the world around him. Later, as he approaches adolescence, his ideas and feelings, __18__    his body, will begin to change. His outlook on the world will broaden. When he has passed through his teenage years, he’ll face the choices of young adulthood: marriage,family, career. Through the thirties, his life may go smoothly, but __19__   another “passage” will approachnear “midlife,” as he reaches his forties. At that point, time will “ __20__   .” Suddenly, he will find himselfin his sixties or seventies, fast approaching the end of his life.
【題組】16
(A) decline
(B) have changed
(C) will tour
(D) will be spent