A small boat being rowed down a river.
A boat is being towed in a river.
Whether a boat is being rowed or being towed, they can both be considered as going in a river.
exists e1 s1 s2 x1 x2 x3.(a_topic(x1) & a_down(s2) & Manner(e1,s2) & Recipient(e1,x3) & Theme(e1,x2) & v_row(e1) & n_river(x3) & (x1 = x2) & n_boat(x1) & a_small(s1) & Theme(s1,x1))
exists e1 x1 x2.(in(e1,x2) & n_river(x2) & Theme(e1,x1) & v_tow(e1) & n_boat(x1))