This is possible because language is not the only symbolic means of communication. In order to prove that chimpanzees and gorillas are capable of language, and not simply a different kind of symbolic communication system, they must learn a sign language with the basic characteristics of human language.
Definition of Halloween. : October 31 observed especially with dressing up in disguise, trick-or-treating, and displaying jack-o'-lanterns during the evening.
Trick-or-treating is the most widely recognized Halloween tradition. It is an activity in which children go from house to house asking for treats (i.e. candy) with the question, Trick or treat? Trick-or-treating is done with children donning Halloween costumes and it is one of the main traditions of Halloween.