河北省正定县2015
高考英语暑假练习（5）（答案或解析）
阅读下面短文，从每题所给的四个选项(a、b、c和d)中，选出最佳答案。
disposing(处理)of waste has been a problem since humans started producing it.as more and more people choose to live close together in cities,the waste-disposal problem becomes increasingly difficult.
