题目

阅读理解     阅读文章，从A、B、C、D四个选项中选出能完成句子或回答问题的正确选项  There are about 56 million people in the United Kingdom. This is a big population for such a small country. But large parts of the country have few people. Most of the population is crowded into the big cities and industrial (工业的)areas. About 90% of the people live in cities and towns. Only about 10% live in the countryside. Today very few people----less than 2% of the population are farmers and farm workers.   England has the most people. About 46 million live in En燃烧硫铁矿产生SO2，为了提高生成SO2的速率，下列措施可行的是（　　） A、把块状矿石碾成粉末B、降低O2的浓度C、使用负催化剂D、降低温度