علی محمد فضیلت فر

If an adequate picture of reading comprehension deficits is to be obtained, the problem of structural knowledge needs to be explored. Once the words in a sentence are recognized, the structure of the sentence needs to be figured out. This understanding plays a crucial role in helping the readers to compute the appropriate relationship between the "people or objects" referred to in the sentences. Individual words within the sentences as well as their order influence the assignment of structural roles to a sentence. Mitchel, Cuetos and Zagar (1990) argue that two kinds of 8 computation are carried out by a reader: understanding the categories of word strings and managing the order in which they appear in sentences. The order of the items used in a sentence like "The dog chased the cat" and its reversal of the roles in the same sentence "The cat chased the dog" illustrate the significance of word ordering in sentence interpretation. Thus, for a reader, a grammatical sentence is not merely a haphazard collection of words, but an arrangement of words which must include identifiable relationships. In this regard, of course, there are formal signals which help readers to recognize sentence structures (Taha, 1983) among which two structures will be discussed later in this article. But we need to explore a little bit about structure understanding before we go to these structures.