An older gentleman cleaning a bicycle rim.
A man works on a bike for his grandson
Men can work on bikes for his own bike, not necessarily just for his grandson.
exists e1 s1 x1 x2 x3 x4.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_clean(e1) & n_rim(x3) & of(x3,x4) & n_bicycle(x4) & (x1 = x2) & n_gentleman(x1) & r_more(s1) & a_older(s1) & Theme(s1,x1))
exists e1 x1 x2 x3.(on(e1,x2) & for(x2,x3) & n_grandson(x3) & of(x3,x1) & n_male(x1) & n_bike(x2) & Actor(e1,x1) & v_work(e1) & n_man(x1))