It is demonstrated that syntactic constructions are the core of a language in synchronic and diachronic perspectives,based on many works of English grammar.From the perspective of cognitive function of language structure,the constructions of events are carriers,entities of form and function and the core of a language.Language knowledge is the knowledge of pairings between form and meaning and the core of the constructions of events.Therefore,it can reveal the natural laws of a language and is an effective approach to language studies and applications to explore the rules of constructions of events from the basic English syntactic constructions on the basis of the inner constructions,rhetoric and cognitive functions of a language.