圆锥形套筒冠义齿固位支持型固位体的内冠内聚角度为（）
A.0°
B.1°～2°
C.2°～3°
D.4°～5°
E.6°
参考答案：E
Most of the mistakes because of carelessness.
A．were made
B．are made
C．has been made
D．were making
泡沫压裂液适用于（）压（）渗和水敏性的储集层。
