Students are preparing for their band demonstration.
The students prepared their demonstration for competition.
Just because the students are preparing for their band demonstration does not mean they are prepared.
exists e1 x1 x2 x3.(for(e1,x2) & n_demonstration(x2) & of(x2,x3) & n_band(x3) & of(x2,x1) & n_thing(x1) & Actor(e1,x1) & v_prepare(e1) & n_student(x1))
exists e1 x1 x2 x3.(n_demonstration(x2) & of(x2,x1) & n_thing(x1) & n_student(x1) & for(e1,x3) & n_competition(x3) & Theme(e1,x2) & Actor(e1,x1) & v_prepare(e1))