恒牙列最常缺失的牙齿是()
A．上颌第三磨牙
B．上颌侧切牙
C．下颌第三磨牙
D．三者均是
E．三者均不是
参考答案：C
The first question was difficult , but ___ were quite easy.
A．the second
B．the other
C．another
D．the rest
奥林匹克青年营的发端是（）年。
A.1935
B.1962
C.1925
D.1912
