دانش چیزی را داشتن ( بیشتر منظور دانش زبانی است )
درکار یا حرفه ای مهارت داشتن
she has a good command of writing/English/cooking
دانش، علم ، تبحر، توانایی،
Have mastery , have the ability to use or control
Knowledge of something especially a language or ability to use something
He has a remarkably command of English.
She has a good command of her emotions