People in costumes are entertaining at an amusement park.
The people are dressed up.
Being dressed up is an other way to say in costumes.
exists e1 x1 x2 x3 x4.(at(e1,x3) & n_park(x3) & of(x3,x4) & n_amusement(x4) & Actor(e1,x1) & v_entertain(e1) & in(x1,x2) & n_costume(x2) & n_people(x1))
exists e1 s1 x1.(n_people(x1) & a_up(s1) & Manner(e1,s1) & Theme(e1,x1) & v_dress(e1))