摘要:Abstract This study investigated the reasons for misunderstanding of the texts available in English book 3 of Iranian high school. In order for a text to maintain its go – togetherness, it should be both cohesive and coherent. That is, it should utilize cohesive devices such as Reference, substitution, ellipsis, conjunctions, and lexical cohesion, the last one of which accounts for the state of coherence in a text. In this analysis, these five cohesive devices have been dealt with in each unit. Based on a calculated frequency, it was shown that the ellipsis and substitutions were the two cohesive devices, which were less often used, in the reading passages of this book. In addition, lexical cohesion pertinent to coherence was hardly used, causing the texts to be incoherent.