A man is sharpening a knife.
A man is sharpening his knife to skin a rabbit.
There are lots of reasons to sharpen a knife, not just to skin a rabbit.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_sharpen(e1) & n_knife(x2) & n_man(x1))
exists e1 p1 x1 x2 x3.(Topic(e1,p1) & exists e2 x4.(Theme(e2,x4) & Actor(e2,x1) & v_skin(e2) & n_rabbit(x4)) & Theme(e1,x3) & Actor(e1,x2) & v_sharpen(e1) & n_knife(x3) & of(x3,x1) & n_male(x1) & n_man(x2) & n_man(x1))