People watch a musician play the guitar.
a guitarist plays for people
If a person is going to play then that person plays
exists e1 s1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_watch(e1) & n_guitar(x3) & (x2 = x3) & n_play(x2) & a_musician(s1) & Theme(s1,x2) & n_people(x1))
exists e1 x1 x2.(for(e1,x2) & n_people(x2) & Actor(e1,x1) & v_play(e1) & n_guitarist(x1))