A dirt biker gets some air over a jump.
A dirt biker did a jump in front of a crowd.
Sentence two may be talking about different dirt biker.
exists e1 x1 x2 x3 x4.(over(e1,x4) & n_jump(x4) & Theme(e1,x3) & Actor(e1,x1) & v_get(e1) & n_air(x3) & n_biker(x1) & of(x1,x2) & n_dirt(x2))
exists e1 x1 x2 x3 x4 x5.(Theme(e1,x3) & Actor(e1,x1) & v_do(e1) & of(x3,x5) & n_crowd(x5) & in(x3,x4) & n_front(x4) & n_jump(x3) & n_biker(x1) & of(x1,x2) & n_dirt(x2))