Two guys are in the air while skateboarding.
guys are skateboarding
Two guys are in the air and are also skateboarding.
exists e1 p1 x1 x2.(n_air(x2) & while(p1,e1) & Actor(e1,x1) & v_skateboard(e1) & in(x1,x2) & n_guy(x1) & card_eq_2(x1))
exists e1 x1.(Actor(e1,x1) & v_skateboard(e1) & n_guy(x1))