8.3 The Gerund

96c) is a mystery that has been noted for some time: why other aspectual and mood morphemes can appear in the gerund but not the continuous one is something that very few approaches can predict. Some have suggested that that the problem is phonological: having two ing forms one following the other for some reason is a problematic sequence. Others disagree and say that the restriction is semantically based. I have nothing to contribute to the discussion and remain as puzzled as ever.