儘管現今已有許多的英語文課外讀物可當作廣泛閱讀的教材，分級讀本（graded readers）還是主要被使用的閱讀書籍，許研究文獻也報告了此類讀本在提升學生閱讀能力的成果。專家們建議為英語為母語者所寫課外讀物（books for native English speaking children）也是非常有用的閱讀材料。本文報告一個四個月的廣泛閱讀課程實驗成果，實驗教學之對象為台灣北部某所國中之兩班國二學生，依班別隨機分為分級讀本組和英語為母語之課外讀物組。兩組均接受每週一小時之實驗教學；實驗前後，兩組學生分別接受英文字彙、文法、閱讀理解能力及閱讀速度測驗之前測和後測。實驗結果顯示，分級讀本組在各項測驗均有顯著進步，然而英語為母語之課外讀物組學生進步情形只在閱讀理解能力及閱讀速度測驗少有顯著差異。此結果顯示，有趣的讀本會吸引學生的注意，自主選擇閱讀材料會提升學生閱讀興趣；但是，學生英語文能力提升與否，讀本語言程度的合適性將會是最主要的原因。

　　　　　Despite the fact that a considerable variety of materials is currently available for extensive reading programs, graded readers (GR) are still the mainstream resource and have been reported as successful in improving learners' reading ability. Some authorities have suggested that books for native English speaking children (BNESC) might be another useful source of reading material. This paper reports on a four-month extensive reading program involving two groups of EFL learners using GR and BNESC respectively. The measures of improvement included vocabulary, grammar, reading comprehension and reading speed tests. An interesting finding was that learners using GR were successful in all of the tests, while learners using BNESC were equally effective in reading comprehension and reading speed tests. This article concludes that while interesting materials will capture learners' attention and the choice of materials will foster their interest, the appropriate structuring of language will enhance their reading ability.