This chapter explores two kinds of intra-clausal relations: grammatical functions and semantic roles. Each such relation allows us to describe the dependencies that exist between a predicator and the units that it combines with to make phrases of various kinds. The grammatical functions discussed include subject, (direct and indirect) object, predicative complement, oblique complement, and modifier. The chapter explores diagnostics used to identify each of these grammatical functions in a sentence. For instance, tag questions, agreement, and subject-auxiliary inversion can tell us if a given constituent is a subject or not. We note here that a key to understanding the syntax of English is the recognition that the mapping between form (categorial type) and function is not one-to-one; mismatches, as when a clause or even a PP serves as a subject, are possible. The chapter describes cases in which a given grammatical function can have various categorical realizations. We see that semantic roles (or participant roles) are combined in the manner they are because they reflect what kind of event, state, or relation the sentence depicts. One cannot, for example, have an event of transfer without a donor, gift, and recipient. The chapter gives examples of semantic roles like agent, theme, patient, location, source, and goal. We observe that, although there are instances in which it is difficult to diagnose an argument’s semantic role, semantic roles can be of use in classifying verbs into distinct subclasses.