翻译The professor in the end dicided to give the prize to whoever he believed had a good command of En

题目

翻译The professor in the end dicided to give the prize to whoever he believed had a good command of English.
had a good command of ?

答案

have a good command of对…掌握熟练；精通
教授最后决定把奖授予他认为对英语掌握熟练的人.