A woman is playing tennis while sitting down in the grass.
The woman is not standing while playing tennis
Not standing is another way of saying sitting.
exists e1 e2 s1 x1 x2 x3.(n_grass(x3) & while(e1,e2) & in(e2,x3) & a_down(s1) & Manner(e2,s1) & Actor(e2,x1) & v_sit(e2) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_tennis(x2) & n_woman(x1))
exists x1.(n_woman(x1) & -exists e1 e2 x2.(while(e1,e2) & Theme(e2,x2) & Actor(e2,x1) & v_play(e2) & n_tennis(x2) & Actor(e1,x1) & v_stand(e1)))