一,引言; 二,元音的性质; 三,已往关於中国声调的结论; 四,现在提出的难题。 一引言 在入题以前,我们应该介绍一些关於中国语的声调的常识。 世界各族语都有所谓“重音”(accent);(1)但重音可分为两种,一种叫做“音高的重音”(accent　de hauteur),另一种叫做“音强的重音”(ac First, the introduction; Second, the nature of the vowels; Third, the previous conclusions on the tone of China; Fourth, the challenge now. I. INTRODUCTION Before entering the question, we should introduce some common sense about the tone of Chinese. There are so-called “accent” in all ethnic groups in the world. (1) Accent can be divided into two types, accent de hauteur and accent de hauteur, (ac