For this type of verb, the potential object is usually semantically limited and therefore can be inferred from the verb at a default value . For instance, for (4a), the listener/reader automatically assumes that John ate "something." What necessitates the object in (4c) is the distinction from the default meaning achieved by specifying what John ate . As a result, this type of verbs can be treated the same as transitive verbs. The theta-roles of "agent" and "theme" can be assigned: