填空题A. library B. post office C. market D. England E. tourist F. ticket G. umbrella

填空题People who live in heavily industrialized areas do not get as much sunshine as they should. Dust floating over a city at the height of more than 4,000 feet cuts between 20 and 50 percent of sunlight and up to 90 percent of ultraviolet light (紫外线). 1 When materials for burning are burned, whether in a factory or in a home, or in the engine of a car, carbon dioxide (二氧化碳) and carbon monoxide (一氧化碳) are given off. Carbon dioxide in the atmosphere prevents loss of heat and keeps warmth in and slowly raises the temperature of the earth. 2 Carbon monoxide is very poisonous and quite small amounts can kill. 3 Unfortunately, while giving us so much pleasure, cars are also poisoning us. 4 Do you know, for example, that a hundred cars could produce a third of a ton of carbon monoxide and many other poisonous substances every day? When you realize that in Great Britain there are over 18,000,000 motor vehicles (车辆), you can see the greatness of the problem. What the answer then? 5 But what about the millions of cars already in use now? Must they all be thrown away? It would probably be very expensive to make changes in them so that they will have nothing to do with pollution control. A. The amount of dangerous substances sent out by a car is quite astonishing. B. The possible solution is to use high quality oil or buy cars with high quality. C. But dust is not the only thing to worry about. D. Great Britain is one of the most polluted countries in the world. E. This could actually change the climate all over the world. F. Everybody wants to have a motor car, and sometimes when we are caught in a traffic jam it seems as though everybody has already got one. G. Scientists are trying to produce a car engine that gives off no pollution at all.