A man sitting on a boat being watched by police officers.
A drug dealer is being watched by the police.
Not every man on a boat sells drug, there are many reasons for police to watch people.
exists e2 e1 x1 x2 x3 x4 x5 x6.(a_topic(x1) & on(e1,x3) & Actor(e2,x5) & n_officer(x5) & of(x5,x6) & n_police(x6) & Theme(e2,x4) & v_watch(e2) & (x3 = x4) & n_boat(x3) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_man(x1))
exists e1 x1 x2 x3.(n_police(x3) & Actor(e1,x3) & Theme(e1,x1) & v_watch(e1) & n_dealer(x1) & of(x1,x2) & n_drug(x2))