A man in shorts is using a barbecue grill in a yard.
Somebody with exposed legs is making food in a backyard.
Just because a man is using a barbecue grill does not mean he is making food.  Even though the many is in a yard does not necessarily mean he is in a backyard.
exists e1 x1 x2 x3 x4 x5.(in(e1,x5) & n_yard(x5) & Theme(e1,x3) & Actor(e1,x1) & v_use(e1) & n_grill(x3) & of(x3,x4) & n_barbecue(x4) & in(x1,x2) & n_shorts(x2) & n_man(x1))
exists e1 s1 x1 x2 x3 x4.(in(e1,x4) & n_backyard(x4) & Theme(e1,x3) & Actor(e1,x1) & v_make(e1) & n_food(x3) & with(x1,x2) & n_leg(x2) & a_exposed(s1) & Theme(s1,x2) & n_person(x1))