They are overview , vowels , consonants , syllable stress , rhythm , intonation , supplementary units 其中的主题有概论,母音,子音,音节重音,节奏,语调,补充单元。
2.
The international system uses two supplementary units that are based on abstract geometrical concepts rather than physical standards 国际制度采用了两种辅助单位,其依据于抽象的几何概念而非物理标准。