Man working on old truck while child watches.
A child watchese as a man repairs his vehicle.
To say someone is working on something, like an old truck, usually presupposes that the person is repairing it. A truck is a type of vehicle.
exists e1 s1 x1 x2 x3 x4 x5.(a_topic(x1) & while(e1,x4) & n_watch(x4) & of(x4,x5) & n_child(x5) & on(e1,x3) & n_truck(x3) & a_old(s1) & Theme(s1,x3) & Actor(e1,x2) & v_work(e1) & (x1 = x2) & n_man(x1))
(x)