a construction worker prepping for roof work.
A plumber preparing the underground pipes.
The worker can't be prepping for roof work and preparing underground pipes at the same time.
exists e1 x1 x2 x3 x4 x5.(a_topic(x1) & for(e1,x4) & n_work(x4) & of(x4,x5) & n_roof(x5) & Actor(e1,x3) & v_prep(e1) & (x1 = x3) & n_worker(x1) & of(x1,x2) & n_construction(x2))
exists e1 s1 x1 x2 x3.(n_pipe(x3) & a_underground(s1) & Theme(s1,x3) & a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_prepare(e1) & (x1 = x2) & n_plumber(x1))