Some phrases containing material nouns are shortened and only the material nouns are left to refer to objects made of them, for example, silver now used for "silver dollar". This is a process of（ ）of meaning.
A、generalization
B、specialization
C、elevation
D、degradation
【正确答案】：B
【题目解析】：本题考查词义的缩小。generalization：词义的扩大；specialization：词义的缩小；elevation：词义的升格；degradation：词义的降格。物质名词转化成专有名词时，词义会发生缩小。用什么材料做成的东西，然后就用材料来作为这种东西的名称，例如：silver可以用作silver dollar（银元）。故B选项符合题意。
