题目

Andy rode slowly on his way to school, day-dreaming about the fishing trip that his father had promised him．He was so busy dreaming about all the fish he would catch that he was unaware of everything else around him．        He rode along until a strange around drew him to the present．He came to a stop and looked curiously up to the heavens．What he saw shocked and terrified him． A huge swarm of bees filled the sky like black cloud and the buzzing mass seemed to be heading angrily towards him．        With no time to waste, Andy sped off in the opposite direction, riding w环境污染有越来越严重的趋势，从生物圈的功能上分析，造成这一结果的原因是A．自动净化能力被阻断B．工业排放废物的增加C．物质循环回路被阻断D．物质循环在一定程度上被阻断