地层温度每增加l℃要向下加深的距离称为()。
A.地温级率
B.地温梯度
C.地层温度
D.井筒平均温度
参考答案:A
Now the air in our city is _______ than it used to be. Something must be done to stop it.[ ]
A. very good
B. much better
C. rather bad
D. even worse
按经济类型分,占电力消费量最少的是( )
A.非金属矿物制品业
B.私营企业
C.外商投资企业
D.烟草制品业耗电量