People enjoying themselves on Jet Skis.
Humans are on jet skis.
People are humans.
exists e1 x1 x2 x3 x4 x5.(ne_org_skis(x4) & (x4 = x5) & ne_org_jet(x5) & n_group(x3) & a_topic(x1) & on(e1,x4) & Theme(e1,x3) & Actor(e1,x2) & v_enjoy(e1) & (x1 = x2) & n_people(x1))
exists p1 x1.(exists x2 x3.(on(x1,x2) & n_ski(x2) & of(x2,x3) & n_jet(x3)) & n_human(x1))