A warehouse under construction.
A warehouse building.
A warehouse is a building, whether or not it is under construction.
exists x1 x2.(a_topic(x1) & under(x1,x2) & n_construction(x2) & n_warehouse(x1))
exists x1 x2.(a_topic(x1) & n_building(x1) & of(x1,x2) & n_warehouse(x2))