填空题

The advantages and disadvantages of a large population have long been a subject of discussion among economists. It has been argued that the supply of good land is limited. To feed a large population, inferior land must be (36) and the good land worked (37) . Thus, each person produces less and this means a (38) average income than could be obtained with a smaller population. Other economists have argued that a large population gives more (39) for specialization and the development of (40) such as ports, roads and rail ways, which are not likely to be built unless there is a big demand to (41) them. One of the difficulties in carrying out a (42) birth control program lies in the fact that official attitudes to population growth (43) from country to country depending on the level of industrial development and the availability of food and raw materials. In the developing country where a vastly expanded population is pressing hard upon the limits of food, space and natural resources, (44) . In a highly industrialized society the problem may be more complex. (45) . When the pressure of population on housing declines, prices also decline and the building industry is weakened. Faced with considerations such as these, (46) .