The sailboarder is falling in the water.
The sailboarder is falling fast in the water.
The sailboarder may be falling, but it's not necessarily a fast fall.
exists e1 x1 x2.(n_water(x2) & n_sailboarder(x1) & in(e1,x2) & Actor(e1,x1) & v_fall(e1))
exists e1 s1 x1 x2.(n_water(x2) & n_sailboarder(x1) & in(e1,x2) & a_fast(s1) & Manner(e1,s1) & Actor(e1,x1) & v_fall(e1))