2.1. Cohesion
A clear definition of cohesion is shown from the work of (Halliday & Hasan, 1976) which divides of cohesion into five distinguished elements: reference, substitution, ellipsis, conjunction, and lexical cohesion. First, in his definition, he elucidates the term ‘reference’as the use of pronouns, articles, and demonstratives. Second, substitution refers to the ability to replace superfluous words. Third, an ellipsis is the elimination of unessential words. Fourth, conjunction refers to the use of an additive, causal, adversative, continuative and adverbial phrases across phrases and sentences. Fifth, lexical cohesion covers word reiteration, super ordinates, synonyms, and collocations or word friends.Cohesion in writing is one of the determinant factors supports the quality learner's writing. The importance of cohesion in writing is initiated by Cameron et al., (1995). They claim that 15% of good writing is derived from cohesion itself. A study from Cox et. al. (1990) indicates that cohesion significantly correlated with EFL learners’ writing quality. By cohesion, it can help teacher pinpoint learner's difficulty in composing a well-written paragraph.