Many two-person kayaks fill a river surrounded by trees.
People are on a kayaking tour.
Two-person kayaks filling a river surrounded by trees is not necessarily on a kayaking tour.
exists e1 e2 s1 x1 x2 x3 x4.(Theme(e2,x2) & Actor(e2,x1) & v_fill(e2) & Actor(e1,x4) & n_tree(x4) & Theme(e1,x3) & v_surround(e1) & (x2 = x3) & n_river(x2) & n_kayak(x1) & a_two-person(s1) & Theme(s1,x1) & n_quantity(x1))
exists p1 x1.(exists e1 x2.(on(x1,x2) & n_tour(x2) & Actor(e1,x2) & v_kayake(e1)) & n_people(x1))