The goal of the project is to analyze the relations between functions and forms within the circumstantial modifications in Czech. Our analysis benefit from multi-layer architecture of the Prague Dependency Treebanks (developed at the applicant´s department) where the form-function relation is understood as a relation between the two layers of the system. We develop the result of the previous project GA17-12624S, in which the forms and functions of the temporal and spatial modifications have been elaborated. In the current project, we apply the acquired experience to the whole area of circumstantial modifications (manner, measure, causal, regard, etc.). Special attention will be paid to secondary forms of expressing circumstantial meanings. A case study on the universality and language specificity of circumstantial functions will be carried out. The main result of the project will be a comprehensive description of circumstantial modifications (monograph). Theoretical knowledge will be shared with the international linguistic community.