ABSTRACT Audry, Christian Lilo. (2021). Investigating Grammatical Patterns of Adjective Clause of English Text for High School Education. A paper. English Department. Faculty of Education and Teacher Training, Universitas Tidar. Keywords: Adjective Clause, workbook, EFL learners, texts, grammatical patterns. Nowadays, in this 21st century, students, especially EFL learners, should learn Engl…