Passage 17
　　
　　A mysteriousblack cloudapproaches the earth-our planet's weather is severely affected.
　　Throughout the rest of June and July temperatures rose steadily all over the Earth. In the British isles the temperature climbed through the eighties, into the nineties, and moved towards the hundred mark. People complained, but there was no serious disaster.
　　The death number in the U. S. Remained quite small, thanks largely to the air-conditioning units that had been fitted during previous years and months. Temperatures rose to the limit of human endurance throughout the whole country and people were obliged to remain indoors for weeks on end. Occasionally air-conditioning units failed and it was then that fatalities occurred.
　　Conditions were utterly desperate throughout the tropics(热带地区)as may be judged from the fact that 7943 species of plants and animals became totally extinct. The survival of　Man himself was only possible because of the caves and cellars(地窖)he was able to dig. Nothing could be done to reduce the hot air temperature. More than seven hundred million persons are known to have lost their lives.
　　Eventually the temperature of the surface waters of the sea rose, not so fast as the air temperature it is true, but fast enough to produce a dangerous increase of humidity(湿度). It was indeed this increase that produced the disastrous conditions just remarked. Millions of people between the latitudes of Cairo and the Cape of Good Hope were subjected to a choking atmosphere that grew damper and hotter from day to day. All human movement ceased. There was nothing to be done but to lie breathing quickly as a dog does in hot weather.
　　By the fourth week of July conditions in the tropics lay balanced between life and total death. Then quite suddenly rain clouds appeared over the whole globe. The temperature declined a little, due no doubt to the clouds reflecting more of the Sun's radiation back into space, But conditions could not be said to have improved. Warm rain fell everywhere, even as far north as Iceland. The insect population increased enormously, since the burning hot atmosphere was as favorable to them as it was unfavorable to Man many other animals.

　　81. In the British Isles the temperature 　　　　　.　　
　　A)stayed at eighty　　　　　　
　　B)ranged from eighty to ninety
　　C)approached one hundred 　　
　　D)exceeded the hundred mark
　　
　　82. Few people in the United States lost their lives because　　　　　.　　
　　A)the temperature was tolerable
　　B)people remained indoors for weeks
　　C)the government had taken effective measures to reduce the hot temperature
　　D)people were provided with the most comfortable air-conditioners
　　
　　83. Millions of people in Cairo(开罗)and the Cape of Good Hope(好望角)were subjected to a choking atmosphere because　　　　　.　　
　　A)the temperature grew extremely hot
　　B)the temperature became damper and hotter as the humidity of the surface waters of the sea increased
　　C)their conditions were too dangerous
　　D)nothing could be done with the hot temperature
　　
　　84. By the fourth week of July conditions in the tropics were such that　　　　　.　　
　　A)human survival would be impossible
　　B)more and more people would lose their lives
　　C)fewer people could be saved
　　D)survival or death was still undecided
　　
　　85. The insect population increased due to　　　　　.　　
　　A)the hot air 　　
　　B) the tropical climate 　　
　　C)the rain clouds　　
　　D)the damp atmosphere

　　答案：　C　D　B　D　A