On October 31st,many children dressed in costumes（節(jié)日服裝）knock on their neighbors' doors and say "Trick or Treat" when the door opens.Pirates and princesses,ghosts and popular heroes of the day all hold bags open to catch the candy or other goodies that the neighbors drop in.As they give each child a treat the neighbors exclaim over the costumes and try to guess who is under the masks.