Re-defined primitives of each syntactic category
As can be seen from the above example，the numbers of np will be very large as well as vp or adj class.In order to reduce the number of words in the same category，a new classification of verbs and other categories need to be redefined，ie.the distinctive semantic components of each syntactic category has to be defined.As these distinctive features will distinguish the syntactic status of next word in doubt.For example，transitive verbs such as broke，cut，touch，and hit all belong to same verb category.To distinguish between them is to find out the crucial distinctive components of each word.Using Levin's terminology，they belong to category of Body-part possessor ascension，Causative/inchoative，Conative，and Middle Construction.The following examples show how these semantic primitives have a crucial role in determine the next word's syntactic category：
a.The little boy broke the window.
b.The window broke.
a.Margaret cut the bread.
b.*The bread cut.
a.Margaret cut the bread.
b.The bread cuts easily.
a.Terry touched the cat.
b.*Cats touch easily.
a.Carla hit the door.
b.Carla hit at the door.
a.Janet broke the vase.
b.*Janet broke at the vase.
a.Margaret cut Bill's arm.
b.Margaret cut Bill on the arm.
a.Janet broke Bill's arm
b.*Janet broke Bill on the arm.
As can be seen from the above examples，break，cut，hit and touch are all transitive verbs taking 2 arguments but their utterance patterns differ.Break is a pure change of state verb，indicating that the state of something has altered，but it does not entail the notion of contact or motion.Cut on the other hand does require the notion of contact and motion in order to cause a state to be changed.It causes of a change of state.Hit differs from touch in that it also implies motion，i.e.contacting something through motion，while touch does not，it is a pure word for contacting.As soon as these distinctive primitives have been verified during utterance processing，their syntactic status will already to be identified.It is argued that verbs can be broken into classes based on their shared properties.
The point should be emphasised on that a single alternation is not sufficient to distinguish a verb class，but by studying several distinct alternations simultaneously，we get a more accurate and revealing pattern of shared behaviour for use in creating distinct verb classes.
Table 1 Selected Verb Classes and Four Diathesis Alternations
