Despite a long history in the theoretical literature, there is no consensus as to why some predicates can be tough-predicates (difficult, easy) but others cannot (long, quick). In this paper, I explore the natural class of tough-predicates, illustrating that they can be defined using two parameters: eventivity and modality. I then explore what the correlation between tough-predicates and for-CPs is, arguing that for-CPs describe properties of contentful events, adopting ideas from Hacquard (2006), Moulton (2009), et seq. The study proposes a natural class of tough-predicates, highlights a universal correlation between tough-predicates and non-finite clauses, and proposes a generalized schema for the meaning of (finite and non-finite) CP clauses.