A man is working to repair a machine.
A man is sweating while working on a machine.
You do not need to be sweating to be working.
exists e1 p1 x1.(Topic(e1,p1) & Actor(e1,x1) & v_work(e1) & exists e2 x2.(Theme(e2,x2) & Actor(e2,x1) & v_repair(e2) & n_machine(x2)) & n_man(x1))
exists e1 e2 x1 x2.(while(e1,e2) & on(e2,x2) & n_machine(x2) & Actor(e2,x1) & v_work(e2) & Actor(e1,x1) & v_sweat(e1) & n_man(x1))