Combinations of a locative preposition and an infinitive are often used to express aspectual relations. In Dutch the relevant combinations are those with aan het, op and uit. The first is the most studied, but also the least understood: its syntactic status is a bone of contention (Broekhuis et al. 2015), and the study of its meaning is skewed by the near-exclusive focus on the combination with zijn ‘be’. According to Coppen (2021) it is the greatest parsing mystery in Dutch grammar. A recent attempt to get out of the impasse is Bogaards et al. (2022). It includes other combinations than those with zijn, draws a distinction between progressive and ingressive uses and shows that this semantic distinction correlates with syntactic differences. This is a step forward. Less felicitous, though, is the sui generis approach of the analysis, involving the postulation of ad hoc syntactic categories (AANHET1(P) and AANHET2(P)). It also has some descriptive and technical problems. As an alternative this article proposes an analysis that is cast in terms of independently motivated categories and distinctions, that avoids the technical problems and that is straightforwardly extensible to the op- and uit-infinitives. For empirical grounding and exemplification we employ two treebanks of contemporary Dutch.