A tropical fisherman throws an orange net into a river.
A fisherman is trying to catch a sea monster.
Just because a fisherman throws a net  into the river it does not mean he is trying to catch a sea monster.
exists e1 s1 x1 x2 x3 x4.(into(e1,x4) & n_river(x4) & Theme(e1,x2) & Actor(e1,x1) & v_throw(e1) & n_net(x2) & of(x2,x3) & n_orange(x3) & n_fisherman(x1) & a_tropical(s1) & Theme(s1,x1))
exists e1 p1 x1.(Topic(e1,p1) & Actor(e1,x1) & v_try(e1) & exists e2 x2 x3.(Theme(e2,x2) & Actor(e2,x1) & v_catch(e2) & n_monster(x2) & of(x2,x3) & n_sea(x3)) & n_fisherman(x1))