A fisherman fishes at the bank of a foggy river.
A fisherman fishes by a foggy river.
If a fisherman fishes by a foggy river, then a fisherman must also be fishing at the bank of the river.
exists e1 s1 x1 x2 x3.(n_bank(x2) & at(e1,x2) & of(x2,x3) & n_river(x3) & a_foggy(s1) & Theme(s1,x3) & Actor(e1,x1) & v_fish(e1) & n_fisherman(x1))
exists e1 s1 x1 x2.(by(e1,x2) & n_river(x2) & a_foggy(s1) & Theme(s1,x2) & Actor(e1,x1) & v_fish(e1) & n_fisherman(x1))