mastery
🇬🇧/ˈmɑːstəri/ 🇺🇸/ˈmæstəri/If you show mastery of a particular skill or language, you show that you have learned or understood it completely and have no difficulty using it. 掌握
noun [抽象名词] 精通，熟练掌握；控制，驾驭
He doesn't have mastery of the basic rules of grammar. 他没有掌握基本的语法规则。
master(精通) + y → 精通， 熟练
