因为银汞合金具有（），所以用银汞合金充填中龋或深龋需要垫底
A.传导性
B.溶解性
C.膨胀性
D.变色性
E.流动性
参考答案：A
It was the first time that a Canadian ________ a gold medal in a Winter Olympics . [ ]
A. won
B. has won
C. had won
D. was winning
2岁（）
A.34cm、32cm
B.46cm、46cm
C.48cm、49cm
D.50cm、54cm
E.54cm、68cm
