Enhancing Conjunction: Internal Temporal Relations

Halliday & Matthiessen (2004: 545):

Many temporal conjunctives have an ‘internal’ as well as an ‘external’ interpretation; that is, the time they refer to is the temporal unfolding of the discourse itself, not the temporal sequence of the processes referred to.  In terms of the functional components of semantics, it is interpersonal not experiential time.