Alinguistictheoryisconstructedaboutwhat______isandhowitworks.
C
语言的研究过程可以总结为：首先，要观察某些语言材料，从而发现一些共性并对其加以总结;其次，根据这些总结提出一些假设来解释这些语言材料，然后再通过进一步的观察来验证这些假设的正确性;最后建立一套语言学理论来说明语言的本质内容以及这些语言是如何发挥作用的。
He talked a lot about things and persons ________they remembered in the school.
Johnson was ________ unknown before running for the presidency.
The thief took away the woman ’s wallet without ________.
_______ is a fact that English is being accepted as an international language.