矿用炸药是泛指各类（）及矿山采剥作业爆落岩石所应用的炸药。
A、矿山基建
B、矿山井巷工程掘进
C、矿山采准
D、矿床开拓
参考答案：B
The government has taken ______measures to stop pollution, hoping to call the attention of all people
to face the problem. [ ]
A. a great many
B. a great deal of
C. a plenty of
D. a large amount of
自发机制和人为机制
