Today we'll talk about reading．When

Today we'll talk about reading．When we read a text，our eyes move across a page in short，quick movements．We recognize words usually when our eyes still fixate(停留，凝视)．Each time they fixate，we see a group of words．This is known as the recognition span or the visual span．The length of time for which the eyes stop varies from person to person．It also varies within any person according to his purpose in reading and his familiarity with the text．In addition，it can be affected by such factors as lighting and tiredness.Unfortunately，in the past，many reading improvement courses have concentrated too much on how our eyes move across the page．As a result of this misleading emphasis on the purely visual aspects of reading，many exercises have been designed to train the eyes to see more words at one fixation．For example，in some exercises，words are flashed on to a screen for a tenth of a second．One of the exercises has required students to fix their eyes on some central point，taking in the words on either side．Such word patterns are often formed in the shape of pyramids，so the reader takes in more and more words at each successive（连续的）fixation．All these exercises are very clever，but it's one thing to improve a person's ability to see words and quite another thing to improve his ability to read a text efficiently. Reading requires the ability to understand the relationship between words．Consequently，for these reasons，many experts have now begun to question the usefulness of eye training，especially since any approach which trains a person to read isolated(孤立的)words and phrases would seem unlikely to help him in reading a continuous text．