沈阳市的地铁工程正在顺利进行．地铁的铁轨通常是由锰钢制成的，锰钢属于（ ）
A．金属材料
B．合成材料
C．复合材料
D．无机非金属材料
答案：A
He proved himself a true gentleman and the beauty of his________was seen at its best when he
worked with others. [ ]
A . advantage
B. appearance
C. qualification
D. character
井喷
