I have a large and ever-growing collection of notes to myself on linguistic topics. This morning I came across one of these notes, a slip of paper with the following example on it:
(1) They came by bearing pizza, after which we watched The Music Man.
(The note doesn’t identify the source of the sentence or the date when I collected it.)
On the most straightforward reading, this sentence has a summative relative clause, “after which we watched The Music Man“, in which the relativizer which refers to the event of some people’s coming by bearing pizza; that is, (1) asserts describes two events, an arrival-with-pizza event and a movie-watching event, occurring in that order. In still other words, (1) is paraphraseable as
(2) They came by bearing pizza, after which event we watched The Music Man.
(In fact, some usage writers insist that (1) is unacceptable, because which has no noun antecedent in the sentence — so that (1) is “vague” — and that something like the clunky (2) must be used instead. See the summatives posting linked to above.)
And now for a subtlety. Although (1) describes only two events, most readers will understand (1) as implicating a third event, of pizza-eating, intervening between the other two, and the author of (1) surely intended this implicature. A nice little case of how sentences can end up conveying more than they literally mean. (The sentence is true if no event of pizza-eating occurred on the occasion in question.)