Bacteria came into a ventilation system when______.A．cool air was sucked into itB．warm air
专四
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Bacteria came into a ventilation system when______.
A．cool air was sucked into it
B．warm air was sucked back
C．cool air was sucked back
D．warm air was sucked into it
请帮忙给出正确答案和分析，谢谢！
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正确答案：B
细节题。第三段首句指出，20世纪70年代人们发现空调带来的一种危险就是军团病。接下来解释了致病原理：从冷却塔压出的热空气又以某种方式被抽回了进气孔，这些热空气为从室外带进来的致病菌的快速繁殖提供了绝佳的温床，而在室外时，致病菌数量很少，不足以产生危害。可见，细菌是在热空气被抽吸回来时进入通风系统的，故答案为[B]。