功能为穿刺、撕裂食物的为
A．切牙B．尖牙C．前磨牙D．磨牙E．智齿
参考答案：B
When class began, we stopped _______ . [ ]
A. talk
B. talking
C. to talk
D. talked
肾的牛理功能是( )
A．生气B．纳气C．主气D．载气E．调气
