上颌第二双尖牙单根管的约为
A．前伸不平衡B．基托边缘伸展不够C．系带区基托缓冲不够D．侧方不平衡E．义齿磨光面外形不良
参考答案：E
单项选择。
I big eyes and small ears.[ ]
A. has
B. have
C. had
D. am
怎样避免电动机冒烟？
