题目

His collection of ancient pots, old uniforms of the kings and splendid wedding dresses of royal family _____ a small fortune. A. are worth    B. is worthwhile    C. is worth   D. are worthwhile   答案：C（2009?济宁）人类从石器时代进入铜器时代，继而进入铁器时代，铜作为金属材料一直被广泛应用着．下面冶炼铜的方法中，利用了置换反应的是（ ）①C+2CuO2Cu+CO2↑②CO+CuOCu+CO2③H2+CuO═Cu+H2O④Fe+CuSO4=Cu+FeSO4A．①②③B．①③④C．②③④D．①②