People racing on ATV's in full protective garb
Several people participating in an ATV race.
Just because people are racing on ATV's doesn't mean they are participating in an ATV race.
exists e1 s1 s2 x1 x2 x3 x4 x5.(a_topic(x1) & in(e1,x5) & n_garb(x5) & a_protective(s2) & Theme(s2,x5) & a_full(s1) & Theme(s1,x5) & on(e1,x3) & n_'s(x3) & (x3 = x4) & ne_org_atv(x4) & Actor(e1,x2) & v_race(e1) & (x1 = x2) & n_people(x1))
exists e1 s1 x1 x2 x3 x4.(a_topic(x1) & in(e1,x3) & n_race(x3) & (x3 = x4) & ne_org_atv(x4) & Actor(e1,x2) & v_participate(e1) & (x1 = x2) & n_people(x1) & a_several(s1) & Theme(s1,x1))