Sirait SGA, Munthe MV, Hutabarat NMP. The Effect Of Substitution Drill To The Students’ Ability In Understanding Subject-Verb Agreement In Writing Descriptive Text. ISIHUMOR [Internet]. 2026 Jan. 28 [cited 2026 Apr. 18];4(1):86-98. Available from: https://putrapublisher.org/ojs/index.php/isihumor/article/view/1344