Sinaga, B., V. Lumban Raja, and F. Y. A. Ginting. “ERROR ANALYSIS ON THE USING BE OF SIMPLE PRESENT AND SIMPLE PAST TENSES AMONG THE SEVENTH GRADE STUDENTS OF SMP NEGERI 2 NAINGGOLAN”. Kairos English Language Teaching Journal, vol. 3, no. 3, July 2020, pp. 208-23, doi:10.54367/kairos.v3i3.841.