The mechanisms for distributing LDP are：（）A、LDP and RSVPB、RSVP and CEFC、CEF and the FIB tableD、UDP and IPE、A and B

正确答案：B

答案：D

解析：

参考答案：There are altogether five mechanisms of meaning changes.1) Melioration, also known as amelioration or elevation of meaning, is the process whereby words with humble origins are gradually used in positive, or at least neutral contexts.e.g. knight: Anglo-Saxon origin, “a boy”, but through military and feudal associations, acquired the meaning of title of rank.2) pejoration or degradation is the process by which the meaning of words become negative or less favorable. Previously mentioned words such as silly, idiot, moron, imbecile, villain, churl and hussy are good cases in point for the illustration of pejoration. These words have been considered so offensive that they are hardly used in daily speeches.3) Generalization of meaning, also called extension, widening or broadening, refers to the extension of the word range, or the widening the semantic scope of words. It is one of the most common features in the history of words.e.g. noviceOriginally meant “a person admitted to a probationary membership in a religious community”, but today it refers generally to “a beginner”4) Specialization, also known as narrowing or restriction, the opposite of generalization, is the process whereby a word of wide meaning acquires a narrow or specialized sense. In other words, a word which used to have a more general sense becomes restricted in its application and conveys only a special concept in present-day English.The word girl, for example, was used to refer to any young person in Middle English but is restricted to young females from the Early Modern Period on. Specialization of meaning can also be observed in the word fowl, which is now usually restricted to “farmyard hen” with its old meaning of “bird” only retains in a few expressions like the fowls of the air and wild fowl.5) Subjectification is the process by which the meaning of a given word changes from relatively objective to increasingly subjective.e.g. very, originally, French word vrai meaning “true” or “real”; the very knight: true knightNowadays if we say that “Lexicology is very interesting”, we use the word very in a much more subjective sense because someone else may disagree with our personal evaluation.

参考答案：D

正确答案：
答：操作型元数据（Operational Metadata），也就是过程处理元数据，记录的是ETL过程中数据迁移情况，如上次迁移日期，加载的记录数等信息。这部分元数据在ETL加载失败时会非常重要。
一般来说，对于使用ETL工具的数据加载，像迁移调度时间、迁移调度顺序，失败处理等内容都可以在由在迁移工具中定义生成。像上次迁移日期等数据可以建表保存。
如果是手工编写ETL程序的话，操作型元数据的处理会麻烦一些，需要自己来获取和存储。获取的方式，不同的编程方式会不尽相同。