The article presents the syntactic phenomenon of discontinuous structures in Dutch, such as separable verbs and pronominal adverbs. They pose many difficulties for Polish students of Dutch. The article explains more thoroughly the types of separable constructions and the conventions that lead to their creation. Special attention is directed towards cases where the discontinuous forms interlock so that they come to a ‘clash’ of prepositions, e.g. Daar komt het op aan or Jacobs haalt het voorbeeld aan van de academische ziekenhuizen van Nijmegen en Duitsland. This accumulation of prepositions often leads to misunderstandings in the right tone of voice and Polish students’ interpretation of sentences. The correct formation of the interlocking structures is one of the most challenging skills with which the students learning Dutch will be confronted.