Dutch has three types of infinitival complement clauses, which are illustrated in (64). The first type is the bare infinitival accusativus cum infinitivo construction which occurs as the complement of perception verbs like zien'to see' and the causative/permissive verb laten'to make/let'. In the second type, the infinitival marker te'to' must be present. The third type can often be found in the same position as the second type, but is preceded by the preposition-like element om (often translated by English for but different from it by lacking the ability to assign case to the subject of the infinitival clause). Since bare infinitives like (64a) never occur as the complement of a preposition, we will focus below on the te-infinitives in (64b&c), in which PRO stands for the implied subject of the infinitival clause.

The status of om in (64c) is unclear; some regard it as an infinitival complementizer, whereas others consider it a regular preposition. The former position seems the most plausible one. A first argument in favor of this position is that, like the complementizer dat'that', om seems to have no clear semantic content; both are just used to introduce embedded clauses. Another argument in favor of this position is that it is not the case that the verb beloven'to promise' in (64c) selects a PP headed by om; cf. Jan beloofde Marie (*om) dat boek'he promised Marie the book'. Finally, the examples in (65) show that, like dat, om may also appear if an anticipatory pronominal PP is present.

For these reasons we will assume that om is a complementizer. If it turns out that, despite the three arguments given above, the element om is a preposition, one must conclude that it is certainly not a preposition selected by the verb beloven in (64c) or the prepositions naar and tegen in (65).

This subsection discusses whether te-infinitives may occur as the complement of temporal or non-temporal adverbial PPs.