Use this domain for words that indicate event propositions. Event propositions are similar in that they are normally expressed by a subject and a verb, possibly including an object, indirect object, or complement clause. However there are multiple ways in which a language can express an event, such as a passive construction, noun phrase, or subordinate clause. In addition each event type is different in its primary cases, and in the ways those cases are marked. Each event type has subtypes, such as intransitive, transitive, and bitransitive verbs. A great deal of research is needed in order to identify all the variations. Ultimately every verb must be investigated to determine how it behaves in each syntactic construction and how its case relations are marked. No two verbs are entirely alike.