Verbs with no end-point and the Progressive [ABE]
With those durative verbs that have no end-point (play, sing, work, talk, dance, rain, snow, etc.), including verbs of bodily sensation (ache, hurt, itch, feel cold), the Progressive has the effect of perspectivizing the process as seen in progress by an observer (the speaker when the reference point is speech time, the relevant participant when it is in the past):
Something very strange is going on here.
That’s what we were talking about.
There is a noticeable contrast between the temporary, ongoing nature of the progressive as seen by an observer and unbounded duration expressed by the simple Past or Present:
Observed ongoing process Unbounded duration Lamps
were glowing in the dark. Lamps glowed in the dark.
Snow was falling gently. Snow fell gently.
My back is aching. My back aches.
Similarly, habitual events, when combined with the progressive, have limited duration. The use of the progressive implies a temporary situation, whereas the ordinary Present tense suggests greater permanence. Compare:
She is running a fringe theatre group (over the summer holidays). She runs a fringe theatre group (as her permanent job).
