研磨后的零件，其耐磨性、抗腐蚀性和疲劳强度也都有所提高，从而延长了零件使用寿命
参考答案：对
— ______ I finish my homework now?
— No, you ______. [ ]
A. Can, can't
B. Must, mustn't
C. Must, needn't
D. Need, should
一位62岁患者，下前牙残根，因眼科疾病请求会诊以除外病灶。口腔科医生应做的检查为
A．全口腔的检查B．拍下前牙X线片C．下颌牙齿检查D．智齿冠周炎检查E．牙齿松动度检查
