Educational Modelling Languages (EMLs) have been proposed to enable the authoring of models of "learning units" (e.g., courses, lessons, lab practices, seminars) covering the broad variety of pedagogical approaches. In addition, some EMLs have been proposed as computational languages that support the processing of learning unit models by appropriate "Learning Management Systems" (LMSs). In this context, six years ago, IMS Learning Design (IMS LD) was proposed as a computational EML. IMS LD supports the modelling of learning units to a long extent and it has become the reference EML. Nevertheless, the expressiveness of IMS LD is a hot topic that has been discussed by several authors during the last years. This paper contributes to this discussion by analyzing the modelling of three learning units with IMS LD. These examples are used to show how IMS LD can be used to author models of common learning units, but also to identify some issues where the IMS LD expressiveness needs to be enhanced. (Contains 4 figures.)