有色金属
参考答案：
除钢、铁、猛以外的其他金属。
Only in this way, directed by the teacher, ______work out the problem the day before.
A．had they
B．they could
C．could they
D．did they
最主要的交往手段是（）
A、金钱
B、物质
C、语言
D、书信
