A boy is covered in bubbles.
The boy is covered in mud.
Bubbles are not mud.
exists e1 x1 x2.(in(e1,x2) & n_bubble(x2) & Theme(e1,x1) & v_cover(e1) & n_boy(x1))
exists e1 x1 x2.(n_boy(x1) & in(e1,x2) & n_mud(x2) & Theme(e1,x1) & v_cover(e1))