In other words, having a wide knowledge of the English grammar rules is not the only requirement if a learner wishes to have a good English command.

换句话说，拥有足够的语法知识不是精通英语唯一的条件。

youdao

Applicants will be expected to have (a) good command of English.

申请人必须精通英语。

《牛津词典》

A good command of English and Computing is a must as far as the position is concerned.

这个职位要求英语和计算机良好。

youdao

Her easy command of English, relentless hustle and good looks got her noticed by a patron, a manager in the London office of commercial film producer Radical Media.

FORBES: Magazine Article

His fluency in the French language may stand him in good stead in the corridors of Brussels although his command of English is said to be less sure.

BBC: Profile: Greek Pasok leader Evangelos Venizelos