A man sitting outside using his Mac laptop.
He was on a laptop.
A man using his Mac laptop means he was working on a laptop.
exists e1 e2 s1 x1 x2 x3 x4.(a_topic(x1) & for(e1,e2) & Theme(e2,x3) & Actor(e2,x2) & v_use(e2) & n_laptop(x3) & (x3 = x4) & ne_org_mac(x4) & of(x3,x1) & n_male(x1) & a_outside(s1) & Manner(e1,s1) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_man(x1))
exists p1 x1.(n_male(x1) & exists x2.(on(x1,x2) & n_laptop(x2)))