People stand in the surf.
The people are waiting for the tide.
Sentence 1 is missing waiting for tide
exists e1 x1 x2.(n_surf(x2) & in(e1,x2) & Actor(e1,x1) & v_stand(e1) & n_people(x1))
exists e1 x1 x2.(n_tide(x2) & n_people(x1) & for(e1,x2) & Actor(e1,x1) & v_wait(e1))