A dog walks across the sand next to a river in front of rolling hills.
a dog is swimming
The dog is either walking or swimming
exists e1 e2 x1 x2 x3 x4 x5.(n_sand(x2) & to(e1,x3) & in(x3,x4) & of(x4,x5) & n_hill(x5) & Actor(e2,x5) & v_roll(e2) & n_front(x4) & n_river(x3) & r_next(e1) & across(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_dog(x1))
exists e1 x1.(Actor(e1,x1) & v_swim(e1) & n_dog(x1))