【单选题】

The effect of the baby boom on the schools helped to make possible a shift in thinking about the role of public education in the 1920’s. In the 1920’s, but especially in theDepression of the 1930’s, the United States experienced a (31) birth rate. Then with the prosperity (32) by the Second World War and the economic boom that followed, young people married and (33) households earlier and began to (34) larger families than had their (35) during theDepression.Birth rates rose to 102 per thousand in 1946, 106.2 in 1950, and 118 in 1955. (36) economics was probably the most important (37) , it is not the only explanation for the baby boom. The increased value placed (38) the idea of the family also helps to (39) this rise in birth rates. The baby boomers began streaming (40) the first grade by the mid-1940s and became a (41) by 1950. The public school system suddenly found itself (42) The wartime economy meant that few new schools were built between 1940 and 1945. (43) , large numbers of teachers left their profession during that period for better-paid jobs else where.

(44) , in the 1950s, the baby boom hit an antiquated and (45) school system.Consequently, the custodial rhetoric of the 1930s no longer made (46) ; keeping youths aged sixteen and older out of the labor market by keeping them in school could no longer be a high (47) for an institution unable to find space and staff to teach younger children. With the baby boom, the focus of educators (48) turned toward the lower grades and back to basic academic skills and (49) . The system no longer had much (50) in offering nontraditional, new, and extra services to the older youths.
A、at B、on
C、for D、with