More and more of the world’s population are living in towns or cities. The speed at which cities are growing in the less developed countries is (36) __________. Between 1920 and 1960 big cities in developed countries (37) ________ two and a half times in size, but in other parts of the world the growth was eight times their size. The (38) __________ size of growth is bad enough, but there are now also very (39) __________ signs of trouble in the (40) __________ of percentages of people living in towns and percentages of people working in industry. During the nineteenth century cities grew as a result of the growth of industry. In Europe the (41) __________ of people living in cities was always smaller than that of the (42) __________ working in factories. Now, however, the (43) __________ is almost always true in the newly industrialised world: (44) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. Without a base of people working in industry, these cities cannot pay for their growth; (45) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. There has been little opportunity to build water supplies or other facilities. (46) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _, a growth in the number of hopeless and despairing parents and starving children.