患者因右上第一磨牙缺失,要求做烤瓷修复。
灌注印模的烤瓷修复工作模型材料宜选用()
A.熟石膏
B.超硬石膏
C.蜡型材料
D.铅
E.硅橡胶
参考答案:B
如图4-49所示系统无摩擦,网盘及绳索质量不计,m1>m2。在m1由静止向下运动过程中,下述说法正确的是()。
A.系统机械能守恒,动量不守恒
B.系统机械能守恒,动量守恒
C.系统对轮心O的动量矩守恒
D.系统质心作均速直线运动
After that, he knew he could ________ any emergency by doing what he could do to the best of his
ability.[ ]
A. get away with
B. get on with
C. get through
D. get across