我国的《公路沥青路面再生技术规范》建议水泥等活性填料一般不超过（）
A.1%
B.1.5%
C.2%
D.2.5%
参考答案：B
The boy was able to __________ himself when he was very young.
A．dress
B．wear
C．put on
D．wears
覆盖义齿基牙采用根帽覆盖时，如患者龋患率高，为防止继发龋的发生，根帽的冠边缘应位于（）
A.龈上边缘
B.平齐牙龈
C.龈下0.5mm
D.龈下1mm
E.差别不大
