为使基牙牙周应力分布均匀,支托凹底与基牙长轴的夹角应为()
A.10°
B.20°
C.30°
D.40°
E.60°
参考答案:B
My friend Mary is _________beautiful girl, _________girl everyone likes to work with.
A.a , a
B.a , the
C.the, a
D. the , the
X波道中,DME/N的系统延时为()。
A.12μs
B.50μs
C.60μs