求翻译：② 理解与掌握个各类液压元件的功能与用途，尤其对于力士乐的液压元件了解较深，同时还了解SUN、MOOG生产的液压元件；是什么意思？

② understand and master the various functions of hydraulic components and uses, especially for Rexroth hydraulic components to understand deep, and also understand the SUN, MOOG production of hydraulic components;