The fact that verbs take arguments is closely related to the fact that they function semantically as n-place predicates. An intransitive verb like lachento laugh in (1a), for example, functions as a one-place predicate, which can be represented in predicate logic as in (1a'). A transitive verb like lezento read in (1b), on the other hand, takes two arguments and thus functions as a two-place predicate, which can be represented semantically as in (1b'); cf. Section 1.1, sub I, for further discussion.

The semantic representation in (1b') suggests that the two arguments of the transitive verb lachen have more or less the same status; the subject noun phrase Jan and the direct object noun phrase het boekthe book are both needed to saturate the predicate lezen and thus complete the proposition. In another respect, however, their relation to the verb is asymmetrical; the direct object is needed to create a complex predicate het boek lezen to read the book that can be predicated of the subject Jan. In other words, the verb phrase leest het boek in (1b) has the same semantic status as the intransitive verb lachen in (1a), and objects can thus be said to be internal to the one-place predicate that is predicated of the subject of the clause. For this reason, objects are called internal arguments or complements of the verb, while subjects are usually (but not always) external arguments; cf. Section 1.2.2, sub I, for further discussion, and Williams (1980/1981) for the original definitions of these terms.

The previous subsection claimed that subjects are usually external arguments. The addition of the adverb usually is necessary because in contemporary linguistics the terms internal and external argument are used to refer not only to the function of arguments in the saturation of the predicate denoted by the verb, but also (and perhaps primarily) to the thematic roles that these arguments may have. In the prototypical case, an external argument refers to the agent or cause of the event, whereas an internal argument rather refers to a theme, goal/source, or experiencer; cf. also Section 1.2. Since there are cases in which the subject of the clause does not refer to an agent or cause, but to one of the thematic roles typically assigned to internal arguments, the concept of subject cannot be fully equated with that of external argument. A prototypical case is the subject of a passive clause such as (2b), which is said to be not an external but an internal argument of the verb lezento read, just like the direct object of the active clause in (2a).

Section 2.1 will show that there is a group of so-called unaccusative verbs that have the defining property that their subject is not an external agentive argument, but an internal theme argument. That something like this may well be the case can be easily illustrated by the examples in (3), since the thematic role of the subject of the monadic predicate breken in (3b) seems identical to that of the object of the dyadic verb breken in (3a).

From now on, the terms subject and object will be strictly reserved for nominative and non-nominative arguments in the clause, respectively, while the terms internal and external argument will be used for arguments of verbs with specific thematic roles.

External arguments are typically nominal in nature, but this is not necessarily true for internal arguments (complements) of the verb. The examples in (4) show that complements can also be prepositional or clausal; for each example we give the complement of the verb in italics and the phrase predicated of the subject of the clause in square brackets.

The strings consisting of the verb and its complement are constituents. This can be seen from the complex verb constructions in (5): the primed examples show that the phrases in brackets can be moved into the main-clause initial position by topicalization, which is sufficient to assume that they are constituents (cf. the constituency test). Since these constituents are headed by a verb, they will be referred to as verbal projection or verb phrase (VP); the trace t in the primed examples is used to indicate the original position of the topicalized VP.

The examples in (6) are somewhat more complex than ordinary transitive clauses such as Marie sloeg de hondMarie beat the dog, in that they contain not only a verbal predicate but also an additional predicate in the form of an adjectival, prepositional or nominal phrase. Such examples are therefore said to involve secondary predication: the secondary predicates are italicized and the secondary predications are given in brackets. The fact that the secondary predicates are predicated of the direct objects in these examples suggests that the latter are not internal arguments of the verbs, but rather (external) arguments of the secondary predicates. The complements of the verbs are instead the secondary predications as a whole, which are therefore part of the VPs that are predicated of the subjects of the clauses. The secondary predicates in (6) will be referred to as predicative complements or complementives.

The structures proposed in (6) are again supported by the fact that VP-topicalization can pied-pipe the secondary predications; this can be seen from the complex verb constructions in (7) .

This chapter proposes a classification of verbs based on the number and type of arguments they take. Section 2.1 first discusses in more detail the classification in Section 1.2.2, sub II, based on the number and types of nominal arguments; this section is therefore mainly concerned with arguments appearing as subject or (in)direct object. It is immediately followed by a discussion of complementives in Section 2.2; the reason for this is that such secondary predicates can take a nominal external argument that also appears as the direct object or subject of the clause. The traditional definition of (in)transitivity in terms of the number of nominal arguments implies that the term intransitive verb can also be used for verbs such as wachten opto wait for, which take a prepositional instead of a nominal complement. However, such verbs differ from the core cases of intransitive verbs at least as much as transitive verbs in that they also take an internal argument, which happens to be syntactically realized not as a noun phrase, but as a PP. We will discuss such prepositional object verbs separately in Section 2.3. Section 2.4 raises the question as to whether there are also verbs with a (non-predicative) AP-complement. Section 2.5 concludes with a discussion of so-called causative psych-verbs such as ergerento annoy and inherently reflexive verbs such as zich vergissento be mistaken; we will show that these verbs exhibit special behavior in several respects. Because complement clauses do not affect the proposed verb classification in a fundamental way and because they raise a large number of additional questions, they will not be discussed in this chapter, but in Chapter 5, which will be devoted in its entirety to this topic.