In every cultivated language there are two great classes of words, which make up the whole

vocabulary. First, there are those words 【C1】______ which we become familiar in daily conversation, which we 【C2】______ , that is to say, from the 【C3】______ of our own family and from our friends, and 【C4】______ we should know and use 【C5】______ we could not read or write. They 【C6】______ the common things of life with all the people who 【C7】______ the language. Such words may be called "popular", since they belong to the people 【C8】______ and are not excluded 【C9】______ a limited class.

On the other hand, our language 【C10】______ a large number of words which are comparatively 【C11】______ used in ordinary conversation. Their meanings are known to every educated person, but there is little 【C12】______ to use them at home or in the marketplace. Our 【C13】______ acquaintance (熟悉) with them comes not from our mother's 【C14】______ or from the talk of our schoolmates, 【C15】______ from books that we read, lectures that we 【C16】______ , or the more 【C17】______ conversation of highly educated speakers who are discussing some particular 【C18】______ in a style. properly higher above the habitual 【C19】______ of everyday life. Such words are called "learned", and the 【C20】______ between them and the "popular" words is of great importance to a right understanding of language study process.

【C1】______

A．at

B．with

C．by

D．through