Dative adpositions instantiate part-whole/inclusion (⊆) relations that hold between the goal and the direct object in the thematic grids of ditransitives. We assume that the same primitive part-whole relation is found: i) when the dative adposition is used in locative contexts; ii) with genitive adpositions, as shown by the widespread genitive/dative syncretism across natural languages. Instrumental inflections/ad- positions are also an instantiation of the same primitive part-whole relation, but they denote the reverse with respect to genitives/datives (⊇). We describe progres- sive aspectual constructions involving adpositions, crosslinguistically. We propose that the dative adpositions found in progressive periphrases are the lexicalization of the same basic ‘part-whole/inclusion’ content: the part-whole relation does not hold between argumental/thematic material but between two events, one event be- ing the time of reference which is ‘part of’ the time-frame of a second embedded event/set of events. The variation in the adpositions found with the Italian aspec- tual periphrases is accounted for in the terms of the ‘direction’ (⊆) vs. (⊇) of the inclusion primitive predicate that implies different interpretations: progressive vs. prospective aspect, respectively.