直接固位体是防止义齿向脱位起主要固位作用的固位部件。
参考答案：对
"When were you born?" "I was born on _______."[ ]
A. June 1st, 1997
B. 1997, June 1st
C. June, 1997 1st
D. 1st, 1997 June
对个别正常描述不正确的是（）
A．轻微的个别牙倾斜
B．对生理过程无大妨碍
C．轻微的上颌前突
D．第三磨牙萌出不全
E．面有轻微的磨耗
描述不正确的是（）