In 2001 M.I.T. Press published a volume titled Parasitic Gaps, edited by Peter W. Cullicover and Paul M. Postal. Its preface begins as follows:
Parasitic gaps (P-gaps) represented by the underlined gaps subscripted p in example (1), have been an intensely studied subdomain of natural language syntax for almost twenty years.
(1) (a) It was Ernest who pictures of _____________p tended to depress _______________.
(b) No matter which candidate the reporter criticized ________________ immediately after meeting ______________p, he won't vote for you.
Can this be translated into language that we unordained laypersons can understand? In both cases it is easy to imagine some word or phrase that it would make sense to put there the p-subscripted blank is, and both cases the other blank seems to be something that should be left blank. The authors seem to think they are telling the reader what a "parasitic gap" is, but I can't make anything of it.

By the way, what's this: in 2001 M.I.T. Press realised that parasitic gaps had been intensely studied for almost 20 years? How could anyone think that meant other than that p-gaps were pretty-much a brand-new thing and therefore worthy not of less but of much more careful explanation?
– Robbie Goodwin Jun 15 '21 at 22:54