Three people are cooking outside using Two gas grills.
Three people are cooking hamburgers outside using two gas grills.
Just because the people are cooking on gas grills does not mean they are making hamburgers.
exists e1 e2 s1 x1 x2 x3.(for(e1,e2) & Theme(e2,x2) & Actor(e2,x1) & v_use(e2) & n_grill(x2) & of(x2,x3) & n_gas(x3) & card_eq_2(x2) & a_outside(s1) & Manner(e1,s1) & Actor(e1,x1) & v_cook(e1) & n_people(x1) & card_eq_3(x1))
exists e1 e2 s1 x1 x2 x3 x4.(for(e1,e2) & Theme(e2,x3) & Actor(e2,x1) & v_use(e2) & n_grill(x3) & of(x3,x4) & n_gas(x4) & card_eq_2(x3) & a_outside(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_cook(e1) & n_hamburger(x2) & n_people(x1) & card_eq_3(x1))