36篇难题之三：练习14之合金密度

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Calculations of the density of alloys based on
Bernal-type models of the alloy‘s metal component
agreed fairly well with the experimentally determined
Line 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

这篇上来一个长难句，其实不用看太多，只要知道一种方法与另一种方法agreed fairly well with each other就可以了。整个篇章逻辑不难，前面讲两者高度agree，从One difference开始讲Real alloy与B Model的区别。
题目的设置就是考察前面这一半的逻辑，其实就是个简单复述。难就难在后面一半的文章比较难读懂，而选项中有好几项都似是而非地触及后半部分，一下子绕晕了同志们。