A dog walks through the snow.
A dog is is swimming in a pond.
Dogs take walks, and can swim, but can't do both at the same time.
exists e1 x1 x2.(n_snow(x2) & through(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_dog(x1))
exists e2 e1 x1 x2 x3.(in(e2,x3) & n_pond(x3) & Actor(e2,x1) & v_swim(e2) & Actor(e1,x2) & v_be(e1) & (x1 = x2) & n_dog(x1))