Improving the students' vocabulary mastery through cartoon film at the seventh grade students of SMPN 2 Ngemplak Boyolali in the academic year of 2015/2016 (a classroom action research) - Dewi Lestari (Jurusan Pendidikan Bahasa Inggris Fakultas Ilmu Tarbiyah dan Keguruan IAIN Surakarta, 2015)