混合性牙瘤多见于
A．切牙区
B．尖牙区
C．下颌磨牙区
D．前磨牙和磨牙区
E．上颌磨牙区
参考答案：D
下列哪项属异向共同运动（）
A.右注视
B.左注视
C.辐辏
D.上转
E.下转
—____?
—I have a stomachache. [ ]
A. Who are you
B. What's the matter
C. How are you
D. What are you
