A man skis on a snowy mountain.
A man is on vacation.
Not all men who are skiing are on vacation.
exists e1 s1 x1 x2.(on(e1,x2) & n_mountain(x2) & a_snowy(s1) & Theme(s1,x2) & Actor(e1,x1) & v_ski(e1) & n_man(x1))
exists p1 x1.(exists x2.(on(x1,x2) & n_vacation(x2)) & n_man(x1))