The purpose of this paper is to analyze English progressive constructions within the framework of cognitive grammar. Many attempts have been made to account for English progressive constructions, but to our knowledge it is hard to define the meanings of them. In this paper the researchers attempt to analyze English progressive constructions in terms of agentivity and movability. Movability is a new term that the researchers propose to account for the cognitive meanings of English progressive constructions. What we claim is that English progressive constructions can be explained more extensively through a cognitive term ``movability``.