因工件表面粗糙使超声波束产生的漫射叫做()
A、角度调整
B、散射
C、折射
D、扩散
参考答案:B
31. _______ with the present situation, the local government could not find effective measures to reduce the risk of coal mine accidents.
A.Though unsatisfied
B.As unsatisfied
C.Though unsatisfied it was
D.As it was unsatisfied
结合实际分析角色游戏的教育价值。