The so-called SKT constructions in English involve sort of, kind of and type of. This paper looks into the grammatical properties of the constructions and discusses their four main uses: referential, qualifier, adnominal, and adverbial. Based on a corpus-based research of the constructions, the paper first reviews the syntactic, semantic, and pragmatic properties of these four uses and then discusses the properties shared among these four uses as well as the distinctive properties of each use. It also offers a construction-based view in accounting for how the mapping relations between form and functions in the SKT constructions have been changed in the present day of American English.