People surfboarding and standing in the ocean.
People sitting around a fire.
People cannot be surfboarding and standing while sitting.
exists e2 e1 x1 x2 x3.(n_ocean(x3) & in(e2,x3) & Actor(e2,x2) & v_stand(e2) & n_people(x2) & Actor(e1,x1) & v_surfboard(e1) & n_people(x1))
exists e1 x1 x2 x3.(a_topic(x1) & around(e1,x3) & n_fire(x3) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_people(x1))