Several people walk up a staircase.
Humans are laying in the grass.
One can not walk and lay at the same time.
exists e1 s1 s2 x1 x2.(a_up(s2) & Manner(e1,s2) & Theme(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_staircase(x2) & n_people(x1) & a_several(s1) & Theme(s1,x1))
exists e1 x1 x2.(n_grass(x2) & ne_nam_humans(x1) & in(e1,x2) & Actor(e1,x1) & v_lay(e1))