Keywords: Ability, Grammar, Clause, Adjective Clause

Grammar is one of components in English. In learning grammar, a clause is a part that
occurs frequently in textbook. Adjective clause is one of those clauses. Adjective clause is a
dependent clause that modifies noun or pronoun. This research tried to investigate how is the
ability of the eleventh grade students of SMAN 7 Banjarmasin. The research method used
descriptive method and mixed approach. The population in this research were 324 students and
sample taken was 108 students. The instruments used in this research were test and interview.
The result showed that the average of students score of the first and second test was 72.12
(72.12%) that categorized into good category. The percentage of each category from the lowest
to the highest was in whose (62.80%), whom (63.35%), where (64.97%), who (67.06%), why
(80.46%), when (83.15%), which (86.73%) and the usage of that (2.21%). Based on the
research result, it is suggested to the teacher to give more attention in order to help the students’
interest in learning English to develop the students’ ability. The teacher can make teaching and
learning more fun by make a games or quiz that related to the materials. Also, the students need
to learn harder in grammar especially in using adjective clause and consider the important of
learning adjective clause to make a complex sentence.