摘要：The current study examined differential effects of two pre-modification types, syntactic elaboration and syntactic simplification (at the level of syntax and irrespective of problematic lexis), on EST students’ reading comprehension. The purpose was to see whether a priori syntactic elaborative adjustment, given its advantages over simplification, can augment comprehensibility of scientific texts in order to replace simplification adjustment. To carry out the study, three versions of 5 passages including Baseline, syntactically simplified, and syntactically elaborated were provided. All the five passages were relevant to civil engineering and they were modified using two above-mentioned techniques. The subjects of the study were composed of 185 homogenous civil engineering students who participated in different phases. The results revealed that syntactic simplification and syntactic elaboration procedures operated nearly in the same way in orienting the EST texts toward comprehensibility. The results of the study even indicated that students benefited more from elaborated than simplified texts although it was not statistically significant. Therefore, the study supports the view that syntactic elaborative adjustment can be exercised in advance on EST materials for pedagogical purposes since it increases the reading comprehension at the same time keeps unfamiliar syntactic units intact to be learned by EST readers
