A man in a green apron roasts a pig over coals.`
The man roasts the pig.
A man or the man who roasts a pig could be roasting it over coals and roasting it while wearing a green apron.
(x)
exists e1 x1 x2.(n_pig(x2) & n_man(x1) & Theme(e1,x2) & Actor(e1,x1) & v_roast(e1))