sentences:  For instance, in the case of gift giving or reciprocity in defined social relationships, actors display a competence in knowing when a gift should be given or not, how much it should be worth, or, if one should fail to give it or if it lies under the appropriate value, what excuses, defenses and justifications might be acceptable.Someone ignorant of these rules, e.g.a child or someone from a totally different culture would obviously make mistakes (for which they would probably be excused by others).