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This study was designed to assess the relative contributions of vocabulary and syntactic knowledge as predictors of reading comprehension performance. It also sought to investigate the interrelationship between syntactic and word knowledge and reading comprehension performance. Participants included 159 male freshman and sophomore Iranian high school students. Data were collected through the reading section of a retired version of Preliminary English Test (2004), Vocabulary Levels Test, Word Associates Test, and Syntactic Knowledge Test. The results revealed that both grammar and vocabulary scores correlated positively with reading comprehension scores. Also, vocabulary correlated significantly with reading comprehension but not as strongly as syntactic knowledge did. Our analysis revealed that syntax explains a larger portion of the reading variance. To examine whether depth / breadth of vocabulary knowledge or syntax may have more predictive power in reading comprehension performance, multiple-regression analysis was conducted. Beta values indicated that grammar made statistically significant contribution to reading comprehension, although other variables explained the variance on the reading test. The results offer new insights into the significant mediating influence that learner’s knowledge of grammar may have in reading comprehension at low intermediate level.  

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Fluent reading is a multifaceted ability that integrates several linguistic and non-linguistic processes. Accordingly, recognizing the critical components of fluent reading is highly significant in planning and implementing effective reading programs. This study was undertaken to evaluate the predictive power of syntactic knowledge, vocabulary breadth, and metacognitive awareness of reading strategies in the reading fluency of Iranian EFL learners. To this end, a sample of 149 Iranian EFL language learners took the Vocabulary Levels Test, Survey of Reading Strategies Questionnaire (SORS), a TOEFL PBT, and a fluency test. The linear regression results indicated that vocabulary breadth was the first predictor of readers' performance on reading fluency, followed by metacognitive awareness of reading strategies. At the same time, syntactic knowledge was not entered into the regression model. Moreover, the findings confirmed the contribution of both linguistic and non-linguistic processes to reading fluency. Having a clear picture of fluency components can be advantageous to teaching reading comprehension and test score predictability.