Abstract: A system for resolving structural ambiguities in syntactic analysis of natural language, which ambiguities are caused by prepositional phrase attachment, relative clause attachment, and other modifier-modifiee relationships in sentences. The system uses instances of dependency (modification relationship) structures extracted from a terminology dictionary as a knowledge base. Structural ambiguity is represented by indicating that a word in a sentence has several words as candidate modifiees. The system resolves such ambiguity by 1) first searching the knowledge base, which contains dependency information in the form of tree structures, for dependencies between the word and each of its possible modifiees, 2) then assigning an order of preference to these dependencies by means of a path search in the tree structures, and 3) finally selecting the most preferable dependency as the modifiee. The sentences can be analyzed by a parser and transformed into dependency structures by the system.