PENINGKATAN KEMAMPUAN MENULIS EKSPOSISI MENGGUNAKAN STRATEGI PEMBELAJARAN KOOPERATIF GROUP INVESTIGATION (Penelitian Tindakan di Kelas VII SMPN 18 Padang Sumatera Barat) (2015) Enhancement Ability Exposition Writing Using Cooperative Learning Strategy Group Investigation Farel Olva Zuve ABSTRACT This action research generally purpose to improve the skills of writing of exposit…