Two kinds of selection marking

Why does an argument clause contain a meaningless complementizer in languages such as English and German, but not in Mandarin; and why does an adverbial clause occur with a meaningless correlative adverb in the matrix clause in Mandarin, but not in languages such as English and German? Extending the c-selection from one type of sisterhood to another type of sisterhood, this paper recognizes the modification relation as a kind of selection relation, in addition to the familiar kind of argument-taking selection relation. This research argues that dependency marking is seen in different types of sister relations. It shows how Mandarin uses modification markers systematically, but does not use argument markers, also systematically. The paper explains the existence of modification markers in various constructions in Mandarin and in various languages. It lets us gain a better understanding of language variations.