Verb Classes

Each main^6.1 verb in the syntactic lexicon selects at least one tree family^6.2 (subcategorization frame). Since the tree database and syntactic lexicon are already separated for space efficiency (see Chapter 3), each verb can efficiently select a large number of trees by specifying a tree family, as opposed to each of the individual trees. This approach allows for a considerable reduction in the number of trees that must be specified for any given verb or form of a verb. There are currently 53 tree families in the system.^6.3 This chapter gives a brief description of each tree family and shows the corresponding declarative tree^6.4, along with any peculiar characteristics or trees. It also indicates which transformations are in each tree family, and gives the number of verbs that select that family.^6.5 A few sample verbs are given, along with example sentences.