放炮员风险预控存在风险包括（）
A.爆炸材料受撞击爆炸
B.爆炸材料导通爆炸
C.违章放炮引起瓦斯爆炸
D.放炮崩人
参考答案：A, B, C, D
—Elle, _____, but your radio is going too loud.
—Oh, I’m sorry. I’ll turn it down right now.
A．I’d like to talk with you
B．I’m really tired of this
C．I hate to say it
D．I need your help
一个三角形的面积是120平方厘米，如果它的底是20厘米，高是多少？（用方程解）
