题目

由于森林的过量砍伐、草场大面积开垦，土地出现沙漠化，导致我市今年出现了近几年来最严重的沙尘暴天气。沙尘暴天气使空气中增加了大量的 A．可吸入颗粒物      B．一氧化碳        C．二氧化氮        D．二氧化硫 答案：A________ China is a developing country, it also has the world’s largest number of foreign exchange reserves.A. When B. While C. As D. Because