参考答案：B

解析：[听力原文]M: How to control environmental pollution for the sake of people’s health W: There are many methods adopted by the government. But it’s pretty hard. Some purifying de vices are not effective. The effective devices are too expensive. And many developing countries need heavy industries to increase their GDP.Q: What do we learn from the conversation 预读选项可知此题与环境污染有关，可能是对政府就预防和治理环境污染的措施提问，属于事实状况题。由女士话中的And many developing countries need heavy industries to increase their GDP．可推断出女士意思是：由于政府通过重工业推动经济的发展，再加上那些有效的净化设备太昂贵，因此政府不可能完全预防污染。