A mountain biker does a trick on a forest path.
a biker on a forest path for the first time
Just because the biker is on a forest path, does not imply it is the biker's first time.
exists e1 x1 x2 x3 x4 x5.(on(e1,x4) & n_path(x4) & of(x4,x5) & n_forest(x5) & Theme(e1,x3) & Actor(e1,x1) & v_do(e1) & n_trick(x3) & n_biker(x1) & of(x1,x2) & n_mountain(x2))
exists s1 x1 x2 x3 x4.(n_time(x4) & a_first(s1) & Theme(s1,x4) & a_topic(x1) & on(x1,x2) & for(x2,x4) & n_path(x2) & of(x2,x3) & n_forest(x3) & n_biker(x1))