There is a widespread belief among the science world ____ we keep on _____  the earth as we are doing today,

the exist ence of us humans on this planet will be out of the question in some years yet to come.[ ]

A. if; polluting

B. if; to pollute

C. that if; to pollute

D. that if; polluting

微型计算机系统中，下面与CPU概念最不等价的是（）

A.中央处理器 

B.微处理器 

C.主机 

D.控制器和运算器