The word “sandwich” now denotes a popular fast food. It originates from John Montague, Fourth Earl of Sandwich in 18th century. This example shows one of the sources of English vocabulary is（ ） .
A、compound
B、proper nouns
C、back-formation
D、conversion
【正确答案】：B
【题目解析】：Mordern English has a large number of words which come from proper nouns. They include names of people, names of places, names of books and trade names.现代英语中有很多词汇来源于专有名词，包括人名、地名、书名和商品名。
