molecular number

例句：

1. 1.The molecular structure of water is very important in understanding its properties.
   水的分子结构对于理解其性质非常重要。
2. 2. The molecules of the gas are constantly moving around.
   气体的分子在不断移动。
3. 3. The study of molecules has led to many breakthroughs in science and technology.
   分子的研究已经为科学和技术带来了许多突破。