如为残根残冠常需分根后拔除的牙齿是
A.上颌中切牙B.上颌前磨牙C.上颌第一恒磨牙D.下颌中切牙E.下颌近中阻生智齿
参考答案:C
解析:上下颌磨牙,尤其是残根冠,常需分根后拔除。
— Turn off the TV, Jack. ____ your homework now?
— Mum, just ten more minutes, please.
A.Should you be doing
B.Shouldn’t you be doing
C.Couldn’t you be doing
D.Will you be doing
雷达发射前须对进行预热:()
A、磁控管阴极
B、调制器
C、混频器
D、本机振荡器