The Effectiveness of using pictures series in teaching descriptive writing ( an experimental research on the seventh grade students of MTS Negeri Filial Kartasura in the academic year of 2015/2016 - Niken Palupi Kusumawati (Jurusan Pendidikan Bahasa Inggris Fakultas Ilmu Tarbiyah dan Keguruan IAIN Surakarta, 2016)