"configurational" understanding of the grammatical relations is associated with Chomskyan phrase structure grammars (Transformational grammar, Government and Binding and Minimalism). The configurational approach is limited in what it can accomplish. It works best for the subject and object arguments. For other clause participants (e.g. attributes and modifiers of various sorts, prepositional arguments, etc.), it is less insightful, since it is often not clear how one might define these additional syntactic functions in terms of the configuration. Furthermore, even concerning the subject and object, it can run into difficulties, e.g. There were two lizards in the drawer. The configurational approach has difficulty with such cases. The plural verb were agrees with the post-verb noun phrase two lizards, which suggests that two lizards is the subject. But since two lizards follows the verb, one might view it as being located inside the verb phrase, which means it should count as the object. This second observation suggests that the expletive there should be granted subject status. Morphological criteria Many efforts to define the grammatical relations emphasize the role inflectional morphology. In English, the subject can or must agree with the finite verb in person and number, and in languages that have morphological case, the subject and object (and other verb arguments) are identified in terms of the case markers that they bear (e.g. nominative, accusative, dative, genitive, ergative, absolutive, etc.). Inflectional morphology may be a more reliable means for defining the grammatical relations than the configuration, but its utility can be very limited in many cases. For instance, inflectional morphology is not going to help in languages that lack inflectional morphology almost entirely such as Mandarin, and even with English, inflectional morphology does not help much, since English largely lacks morphological case. Prototypical traits The difficulties facing attempts to define the grammatical relations in terms of thematic or configurational or morphological criteria can be overcome by an approach that posits prototypical traits. The prototypical subject has a cluster of thematic, configurational, and/or morphological traits, and the same is true of the prototypical object and other verb arguments. Across languages and across constructions within a language, there can be many cases where a given subject argument may not be a prototypical subject, but it has enough subject-like traits to be granted subject status. Similarly, a given object argument may not be prototypical in one way or another, but if it has enough object-like traits,