A short article introducing the concept of ‘thematic roles’ and its application. Here’s the first paragraph:

Verbs describe a situation involving one or more entities, or arguments. Running, for example, necessarily involves one argument (Mary ran), kicking involves two (Mary kicked the chair) and giving three (Mary gave Sue a book). A thematic role is a general characterization of an argument’s role in the situation described by the verb. For example, an Agent is an argument which initiates and executes the action of the verb. A Theme is an argument which moves or changes state during the verbal action. A Patient is an argument undergoing the verbal action, a Goal is the destination of another verbal argument and an Experiencer is an argument whose mental state is affected or described by the verb. Less familiar thematic roles include Measure (the object in such sentences as Mary weighs 150 lbs), Source (the box in Mary removed the gift from the box), and Incremental Theme (the created or consumed object in Mary ate the apple or Sue wrote a letter).