This paper analyses data to address a specific linguistic problem, i.e. the acquisition of the modification potential of the three more or less synonymous Dutch degree modifiers heel, erg and zeer, all meaning 'very', which show syntactic differences in modification potential. It continues the research reported on in The analysis makes crucial use of linguistic applications developed in the CLARIN infrastructure, in particular the treebank search applications PaQu (Parse and Query) and GrETEL Version 4.00. The analysis benefits from the use of parsed corpora (treebanks) in combination with the search and analysis options offered by PaQu and GrETEL. Earlier work showed that despite little data for zeer modifying adpositional phrases adult speakers end up with a generalised modification potential for this word. In this paper, I extend the dataset considered, and find more (but still little) data for this phenomenon. However, I also find a similar amount of data that form counterexamples to the non-generalisation of the modification potential of heel. I argue that the examples with heel concern constructions with idiosyncratic semantics and therefore are not counted as evidence for the general rule of modification. I suggest a simple statistical analysis to account for the fact that children 'learn' that heel cannot modify verbs or adpositions though there is no explicit evidence for this and they are not explicitly taught so.