Mohammad Yani Pehang, Darmanto Minggele, Hanif Cahyo Adi Kistoro. Improving Understanding And Learning Activities Of Simple Present Tense Declarative Sentences Through Whatsapp-Based Substitution Drills Techniques For Mtsn Students In Kupang City. LN [Internet]. 2024 Nov. 27 [cited 2024 Dec. 19];2(3):1-16. Available from: http://linguanusa.com/index.php/1/article/view/67