A man wearing a white shirt is working on building something.
The man is building a house.
Just because a man is working on building something it does not mean the man is building a house.
exists e3 e2 e1 s1 x1 x2 x3 x4 x5.(on(e2,e3) & Theme(e3,x5) & Actor(e3,x4) & v_build(e3) & n_thing(x5) & Actor(e2,x1) & v_work(e2) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_shirt(x3) & a_white(s1) & Theme(s1,x3) & (x1 = x2) & n_man(x1))
exists e1 x1 x2.(n_man(x1) & Theme(e1,x2) & Actor(e1,x1) & v_build(e1) & n_house(x2))