编辑点评： GRE阅读考试的材料，非常强调逻辑的关系，所以逻辑要点是大家在解GRE阅读题的时候的关键，本文就为大家例举了这样一篇逻辑短文，供大家参考和练习。
随着GRE阅读考试的难度日益增加，大家需要有针对性地进行练习，本文为大家例举的就是逻辑短文的练习，文末还附有答案，供大家更好地练习。
Calculations of the density of alloys based on Bernal-type models of the alloy s metal component agreed fairly well with the experimentally determined values from measurements on alloys consisting of a 5 noble metal together with a metalloid, such as alloys of palladium and silicon, or alloys consisting of iron,phosphorus, and carbon, although small discrepancies remained. One difference between real alloys and the hard spheres used in Bernal models is that the 10 components of an alloy have different sizes, so that models based on two sizes of spheres are more appropriate for a binary alloy, for example. The smaller metalloid atoms of the alloy might fit into holes in the dense, random-packed structure of the larger metal atoms.
4. The author s speculation about the appropriateness of models using spheres of two sizes for binary alloys would be strongly supported if models using spheres of two sizes yielded
○A values for density identical to values yielded by one-sphere models using the smaller spheres only
○B values for density agreeing nearly perfectly with experimentally determined values
○C values for density agreeing nearly perfectly with values yielded by models using spheres of three sizes
○D significantly different values for density depending on the size ratio between the two kinds of spheres used
○E the same values for density as the values for appropriately chosen models that use only medium-sized spheres
答案：B
上文的题目大家答对了几题?大家不仅要多做题，更要善于总结，这样才会有针对性地提高。