牙轮在牙爪轴颈上的固定是通过牙爪下侧背部的斜孔插入销子并焊死来完成的。
参考答案：错
Jack is 40 and he feels his career as ________ actor is coming to ________ end.
A．不填；the
B．the; an
C．an; an
D．an; 不填
既有热塑性又有良好的弹性的防水卷材是( )。
A．再生橡胶改性防水卷材 B．聚氯乙烯防水卷材C．三元乙丙橡胶防水卷材 D．氯化聚乙烯防水卷材
