GRE Text Completion: JiJing 1373-GRE填空机经1373题 - 5A1DP5R6J66FXYVDA

Many metals have very useful properties, such as being good conductors of electricity. However, the majority of metals are too ____________ to be used in their pure form. Instead, they are combined with impurities to be much harder and stronger while still retaining many of the characteristics of the original metal. A. soft B. robust C. unstable D. malleable E. mercurial F. rigid