会导致咀嚼无力的是（）。
A.基托边缘过长或过锐
B.基托变形
C.基托与黏膜不密合
D.人工后牙覆盖过小
E.垂直距离过低
参考答案：E
The policeman asked him when the accident happened. [ ]
A. what was he doing
B. what did he do
C. what he was doing
D. what he did
圆柱孔轴承可使用（）拆卸。
A.压力机或拉力器
B.锤子
C.温差法
