交际礼仪修养
参考答案：
是指人们在社交活动中，通过对交际礼仪规范的学习，训练，达到一定的交际礼议要求和水平。
乳牙患龋达到高峰的年龄是（）
A.3～4岁
B.5～6岁
C.7～8岁
D.9～10岁
E.11～12岁
—Was ______ Bill, ______ played basketball very well, ______ helped the blind man cross the road?
—Yes, of course. He is always ready to help others.
A．it; that; who
B．this; who; that
C．which; that; that
D．it; who; that
