One guy in a white shirt trying to stop another guy in a red shirt from throwing a Frisbee.
Nobody has a hirt
The guys in the first sentence are wearing a white shirt and a red shirt, whereas in the second sentence nobody is wearing a shirt.
exists e1 p1 s1 x1 x2 x3.(a_topic(x1) & in(x1,x2) & Topic(e1,p1) & Actor(e1,x3) & v_try(e1) & exists e3 e2 s2 x4 x5 x6.(from(e2,e3) & Theme(e3,x6) & Actor(e3,x3) & v_throw(e3) & n_frisbee(x6) & Theme(e2,x4) & Actor(e2,x3) & v_stop(e2) & in(x4,x5) & n_shirt(x5) & a_red(s2) & Theme(s2,x5) & n_guy(x4) & -(x4 = x1)) & n_guy(x1) & n_guy(x1) & (x2 = x3) & n_shirt(x2) & a_white(s1) & Theme(s1,x2) & card_eq_1(x1))
-exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & n_hirt(x2) & n_person(x1))