Can 6- and 8-year-olds (and adults) comprehend common instrument verbs when extended to novel situations? Participants heard eight unusual extensions of common verbs and were asked to paraphrase the verbs' meanings. Half of the verbs used were specified instrument verbs that include the name of the instrument used to perform the action (e.g., a vacuum is used to vacuum); the other half were open instrument verbs (e.g., write) whose function can be performed with a range of objects. Results suggest that children's ability to interpret verb extensions increases with age, that open instrument verb extensions were more difficult to comprehend than specified instrument verb extensions and that performance on verb extension correlates with scores on a standardized test of language acquisition. Verb knowledge continues to develop well beyond the preschool years.