This section discusses prepositional object verbs (PO-verbs), i.e. verbs that take a prepositional phrase as their complement. Some examples of such verbs are given in (307). In these examples, the PP-complement is the only internal argument of the verb: since the verb also takes an external argument (realized as the subject of the clause), we will refer to such verbs as intransitive PO-verbs.

The most striking property of the PP-complements in (307) is that they have a fixed preposition, the choice of which is lexically determined by the verb: substituting any other preposition for the preposition op in these examples results in ungrammaticality. The choice of preposition often seems arbitrary, as shown by the fact that the preposition op in the examples in (307) has to be rendered by different prepositions in English: cf. to wait for; to shoot at; to look after. Moreover, the prepositions usually do not have a well-defined semantic content, which is why we will refer to them as functional prepositions. This lack of semantic content shows that the meaning of the combination of the verb and its PP-complement is not built up compositionally, but is listed in the lexicon as a semantic unit.

PP-complements can be found in several syntactic frames. They occur not only with external arguments, as in (307), but also with internal arguments. In (308), for instance, we find verbs that take an internal argument that is realized as an accusative object; such verbs are called transitive PO-verbs.

Since we have seen in Section 2.1.2 that verbs with a single nominal argument can be either intransitive or unaccusative, it will come as no surprise that there are also PO-verbs that exhibit unaccusative behavior. Some examples of such PO-verbs are given in (309); the unaccusative status of the verbs is clear from the fact that they take the perfect auxiliary zijnto be.

Table 7 shows that the three types of PO-verbs in examples (307) to (309) fit well into the classification of verbs based on nominal arguments discussed in Section 2.1: it simply seems to be the case that some intransitive, transitive, and unaccusative verbs can (or must) select an additional PP-complement. These verbs will be discussed in in Section 2.3.2.

	external argument	internal arguments		subsection
		NP	PP
transitive	+	+	+	2.3.2, sub I
intransitive	+	—	+	2.3.2, sub II
unaccusative	—	+	+	2.3.2, sub II

It seems that not all the verb types we distinguished in Section 2.1 can be supplemented with a PP-complement: we are not aware of clear cases of ditransitive or nom-dat verbs that take an additional PP-complement. This suggests that there is an upper limit to the number of internal arguments a verb can take: a verb has at most two internal arguments. Of course, this claim may be too strong; possible counterexamples are verbs of exchange like kopento buy, verkopento sell and betalento pay in (310), for which it has been claimed that they actually have three internal arguments.

The generalization proposed above implies that at least one of the putative arguments in the examples in (310), probably the voor-PP, is an adjunct. Since the distinction between complements and adjuncts is often not immediately clear, both proponents and opponents of assuming adjunct status for the voor-PP may find it difficult to substantiate their position. We will assume that the voor-PPs are adjuncts because they satisfy the adverbial test in (311), which singles out VP adverbials; cf. Section 2.3.1, sub VII, which will show that PP-complements cannot be paraphrased by ... en pronoun doet dat XP clauses. For further evidence for the claim that the voor-PPs in (310) are adjuncts, we refer the reader to the discussion of example (358) in Section 2.3.2, sub I.

The hypothesis that verbs have at most two internal arguments is supported by the fact that there are no ditransitive and nom-dat verbs with and additional PP-complement. Crucially, this cannot be attributed to the presence of a dative phrase, since there are cases in which a verb can take both a dative argument and a PP-complement; this is especially true for ditransitive verbs in which the accusative object alternates with a PP-complement, as illustrated in the examples in (312). This means that the non-existence of ditransitive and nom-dat PO-verbs cannot be due to the mere presence of a dative phrase; it is the number of internal arguments present that counts.

The cases in (313) show that this kind of verb-frame alternation is more general, as it can also be found with certain transitive verbs; cf. Section 3.3.2 for a more detailed discussion of this alternation.

Note that the accusative/PP alternation is highly marked in case the indirect object in (312) is realized as a PP: cf. Van Oostendorp (2022). This suggests that a verb can have at most one PP-complement, which seems to be confirmed by the fact that PO-verbs usually cannot be supplemented with a second PP-complement; cf. Section 2.3.4, sub I, for a relevant discussion. Note that if this restriction is correct, it provides an additional reason for analyzing the voor-PPs in (310) as VP-adjuncts.

The accusative/PP alternation illustrated in (312) and (313) is not possible with all (di)transitive verbs and it often has a subtle effect on meaning. Nevertheless, the nature of the PP-complements seems close enough to that of the nominal complements to merit a separate discussion of such examples; cf. Section 2.3.3. In addition to the examples discussed so far, there are several other cases that merit discussion, which will be taken up in Section 2.3.4. Before we discuss the individual classes, Section 2.3.1 will discuss some properties that all PO-verb constructions seem to have in common. Section 2.3.2 then looks in more detail at the properties of the three main syntactic classes, i.e. intransitive, transitive and unaccusative PO-verbs.