Kids participate in a potato sack race.
The kids are in potato sacks.
If kids are in a potato sack race, then to compete they must be in potato sacks.
exists e1 x1 x2 x3 x4.(in(e1,x2) & n_race(x2) & of(x2,x4) & n_sack(x4) & of(x2,x3) & n_potato(x3) & Actor(e1,x1) & v_participate(e1) & n_kid(x1))
exists p1 x1.(n_kid(x1) & exists x2 x3.(in(x1,x2) & n_sack(x2) & of(x2,x3) & n_potato(x3)))