In linguistics, control is a construction in which the understood subject of a given predicate is determined by some expression in context. Stereotypical instances of control involve verbs. A superordinate verb "controls" the arguments of a subordinate, nonfinite verb. Control was intensively studied in the government and binding framework in the 1980s, and much of the terminology from that era is still used today. In the days of Transformational Grammar, control phenomena were discussed in terms of Equi-NP deletion. Control is often analyzed in terms of a null pronoun called PRO. Control is also related to raising, although there are important differences between control and raising. Most if not all languages have control constructions and these constructions tend to occur frequently. Examples Standard instances of (obligatory) control are present in the following sentences: Susan promised to help us. - Subject control with the obligatory control predicate promise Fred stopped laughing. - Subject control with the obligatory control predicate stop We tried to leave. - Subject control with the obligatory control predicate try Sue asked Bill to stop. - Object control with the obligatory control predicate ask They told you to support the effort. - Object control with the obligatory control predicate tell Someone forced him to do it. - Object control with the obligatory control predicate force Each of these sentences contains two verbal predicates. Each time the control verb is on the left, and the verb whose arguments are controlled is on the right. The control verb determines which expression is interpreted as the subject of the verb on the right. The first three sentences are examples of subject control, since the subject of the control verb is also the understood subject of the subordinate verb. The second three examples are instances of object control, because the object of the control verb is understood as the subject of the subordinate verb. The argument of the matrix predicate that functions as the subject of the embedded predicate is the controller. The controllers are in bold in the examples. Control verbs vs. auxiliary verbs Control verbs have semantic content; they semantically select their arguments, that is, their appearance strongly influences the nature of the arguments they take. In this regard, they are very different from auxiliary verbs, which lack semantic content and do not semantically select arguments. Compare the following pairs of sentences: a. Sam will go. - will is an