The ground is covered in snow.
The snow on the ground has been there for days.
Just because the ground is covered in snow doesn't mean it's been there for days.
exists e1 x1 x2.(n_ground(x1) & in(e1,x2) & n_snow(x2) & Theme(e1,x1) & v_cover(e1))
exists s1 x1 x2 x3.(n_ground(x2) & n_snow(x1) & for(s1,x3) & n_day(x3) & Theme(s1,x1) & a_there(s1) & on(x1,x2))