People laughing while at a restaurant.
People sad and crying on Mars.
People cannot be laughing and sad simultaneously nor can they be at a restaurant and on Mars simultaneously.
exists e1 x1 x2 x3.(a_topic(x1) & at(e1,x3) & n_restaurant(x3) & r_while(e1) & Actor(e1,x2) & v_laugh(e1) & (x1 = x2) & n_people(x1))
exists s1 s2 x1 x2 x3 x4.(ne_geo_mars(x4) & a_topic(x1) & on(x1,x4) & Theme(s2,x3) & a_cry(s2) & (x1 = x3) & Theme(s1,x2) & a_sad(s1) & (x1 = x2) & n_people(x1))