A group of people white water raft on very choppy water.
the birds were short necked
A group of people cannot be referred as birds.
exists s1 x1 x2 x3 x4.(a_topic(x1) & on(x1,x4) & n_water(x4) & a_choppy(s1) & Theme(s1,x4) & r_very(x4) & n_white(x1) & n_water(x1) & Time(x1,x3) & n_raft(x3) & of(x1,x2) & n_people(x2) & n_group(x1))
exists e1 s1 x1.(n_bird(x1) & for(s1,e1) & Theme(e1,x1) & v_neck(e1) & Theme(s1,x1) & a_short(s1))