The man and woman are sitting by the boats.
A man and woman are sitting by a lake.
Boats could be at a lake.
exists e1 x1 x2 x3 x4.(n_boat(x4) & n_woman(x3) & n_man(x2) & subset_of(x3,x1) & subset_of(x2,x1) & by(e1,x4) & Actor(e1,x1) & v_sit(e1))
exists e1 x1 x2 x3 x4.(by(e1,x4) & n_lake(x4) & Actor(e1,x1) & v_sit(e1) & n_woman(x3) & n_man(x2) & subset_of(x3,x1) & subset_of(x2,x1))