何谓坝岸基础淘塌险情？
参考答案：
坝岸的护根石被大溜冲失，引起坍塌，坝身失稳而出险。
Those guests () the front row came here from a European country early this morning.
A．who seated
B．seating
C．were sitting
D．seated
交联挤塑机机身温度过高，容易引起物料（）。
A.硬块
B.分解
C.先期交联
D.外径波动
