近年来这方面的研究开发主要是围绕结构 、 合成 、 表征和催化反应等方面开展的. The Query is "precisely what is the real difference...", but by far the most voted solutions react with "rather than telling you what exactly is the difference I am telling you how you need to work" A class or static variable is usually a variable https://commercialshopsingurgaon.school.blog/2025/06/13/signature-global-plots-farukhnagar-where-your-vision-finds-ground/