A couple of people survey the sea for wildlife.
The people are making sandwiches.
One cannot survey the sea if one is making sandwiches.
exists e1 x1 x2 x3 x4.(n_sea(x3) & Theme(e1,x3) & Actor(e1,x1) & v_survey(e1) & for(x3,x4) & n_wildlife(x4) & of(x1,x2) & n_people(x2) & n_couple(x1))
exists e1 x1 x2.(n_people(x1) & Theme(e1,x2) & Actor(e1,x1) & v_make(e1) & n_sandwich(x2))