A family prepares to ride on the water.
The boat might sink.
Prepares to ride on the water does not imply the boat might sink.
exists e1 p1 x1 x2.(n_water(x2) & Topic(e1,p1) & Actor(e1,x1) & v_prepare(e1) & exists e2.(on(e2,x2) & Actor(e2,x1) & v_ride(e2)) & n_family(x1))
exists e1 p1 x1.(n_boat(x1) & exists e2.(Actor(e2,x1) & v_sink(e2)) & Topic(e1,p1) & Actor(e1,x1) & v_might(e1))