Several girls on a raft floating in rough waters.
The are more than one girls on the boat.
Several implies more than one girl and a raft is a form of boat.
exists e1 s1 s2 x1 x2 x3 x4.(a_topic(x1) & on(x1,x2) & in(e1,x4) & n_waters(x4) & a_rough(s2) & Theme(s2,x4) & Actor(e1,x3) & v_float(e1) & (x2 = x3) & n_raft(x2) & n_girl(x1) & a_several(s1) & Theme(s1,x1))
(x)