36套里面一道题，求各位指点，谢谢啦

walkboyUID: 3056612

Eight percent of the Earth‘s crust is aluminum, and
there are hundreds of aluminum-bearing minerals and
vast quantities of the rocks that contain them. The best
Line aluminum ore is bauxite, defined as aggregates of alumi-
5 nous minerals, more or less impure, in which aluminum
is present as hydrated oxides. Bauxite is the richest of all
those aluminous rocks that occur in large quantities, and
it yields alumina, the intermediate product required for
the production of aluminum. Alumina also occurs natu-
10 rally as the mineral corundum, but corundum is not found in large deposits of high purity, and therefore it is an impractical source for making aluminum. Most of the many abundant nonbauxite aluminous minerals are silicates, and, like all silicate minerals, they are
15 refractory, resistant to analysis, and extremely difficult to process. The aluminum silicates are therefore generally unsuitable alternatives to bauxite because considerably more energy is required to extract alumina from them. (153 words)
4. The author implies that a mineral must either be or
readily supply which of the following in order to be
classified as an aluminum ore?
(A) An aggregate
(B) Bauxite
(C) Alumina
(D) Corundum
(E) An aluminum silicate

肿么不选B呢？定位： The best
Line aluminum ore is bauxite, defined as aggregates of alumi-
5 nous minerals, more or less impure, in which aluminum
is present as hydrated oxides

mmchuanjiao2UID: 3125003

The best Line aluminum ore is bauxite...bauxite只是aluminum ore的一种 是最好的  当然不能选

walkboyUID: 3056612

2# mmchuanjiao2 恩恩，谢了，一下就明白了，哎，看了半天还不如别人指点下