离子交换树脂相互之间碰撞，挤压或经常使树脂发生自身膨胀和收缩，都会引起树脂的（）降低
A.交联度
B.机械强度
C.湿视密度
D.溶解性
参考答案：B
They took the injured straight to the nearest hospital. Otherwise some of them____________
A．died
B．would die
C．might have died
D．could die
简述泥浆固壁的基本原理。
