推动上下牙弓向后发育的动力并非来自（）
A.翼内肌
B.口轮匝肌
C.上下唇弓肌
D.颧肌
E.唇颊肌
参考答案：A
Don't the ball on the ground. It's made of glass. [ ]
A. fall
B. drop
C. put
D. place
塔式起重机基础混凝土垫层厚度不宜小于（）mm。
A.50
B.70
C.80
D.100
