《全日制普通高级中学教科书英语(必修)高三册》(人民教育出版社,2005:80)中有这样一句话:When Fleming returned from thewar,he began searching for the chemical he be-lieved could treat infections.以上句子中出现了关系代词引导定语从句并在从句中作主语时被省略的语法现象。该句 In the “High School of General High School Textbook English (Compulsory) High School” (People’s Education Press, 2005:80), there is a saying: When Fleming returned from the war, he began searching for the chemical he be-lieved could treat infections. The grammatical phenomenon in which the relative pronouns guide the attributive clause and make the subject in the clause appears in the above sentence. Sentence