The use of him (hidden item maker) game to improve students'vocabulary mastery of the seventh grade students of SMP Negeri Ngargoyoso 02 in the academic year of 2014/2015 - Yuliasih (Jurusan Pendidikan Bahasa Inggris Fakultas Ilmu Tarbiyah dan Keguruan IAIN Surakarta, 2016)