In addition to componential aspects of verb meaning, children must also acquire a representation of each verb's combinatorial properties or propositional schema, i.e., the number of arguments with which it is obligatorily or optionally associated. The present study investigated developmental changes in children's awareness of the combinatorial requirements of 22 early learned verbs, through their judgements and corrections of sentences from which obligatory and optional arguments had been omitted. Twenty-five children in each of three age groups (mean ages: 4;4, 7;2, and 10;0) were asked to judge and correct 44 sentences constructed to contrast verb pairs for which the same argument was obligatory or optional. Results showed significant changes across age groups in awareness of verb argument requirements, with this apparent progression: (1) initial ignorance of argument requirements, (2) gradually increasing awareness of these requirements, (3) overgeneralization of requirements to sentences lacking optional arguments, and (4) an adult-like representation of obligatory and optional arguments for each verb. (Author)