Then the combination of these words to form permissible sentences in languages is governed by rules. The study of these rules constitutes a major branch of linguistic studies, i. e., ______.
A、phonetics
B、phonology
C、morphology
D、syntax
【正确答案】：D
【题目解析】：Then the combination of these words to form permissible sentences in languages is governed by rules. The study of these rules constitutes a major branch of linguistic studies, i. e., syntax.