She's proficient in several languages.

她精通好几种语言。

《牛津词典》

A great number of Egyptians are proficient in foreign languages.

大量埃及人精通外语。

《柯林斯英汉双解大词典》

She was very proficient in music.

她非常精通音乐。

youdao

It turns out in the world of classical music there's a stereotype of women being simply less proficient than men: they play smaller than men, they don't have the same force and they have smaller techniques, they're more temperamental and so on.

在古典音乐界,有一个刻板印象,女人的造诣就是不如男人：,她们演奏得不如男人宏大，她们力量不如男人，她们技巧不如男人，她们喜怒无常等等。

耶鲁公开课 - 心理学导论课程节选

Until you're a proficient reader of a language, writing in our language is a fool's errand.

你只有成为一个熟练的读者，才有可能成为一个好的作者。

英语阅读：技巧 - SpeakingMax英语口语达人

Even more staggering, 4% of Detroit public-school 8th graders are proficient in math.

FORBES: Right-To-Work: Does It Improve Teacher Quality?

When they joined the revolution, they were already proficient in the use of small- and medium-sized weapons.

BBC: Covert help for Syria's rebels in Jordan

Candidates must be proficient in reading and writing the language of instruction in the proposed country of study.

UNESCO: Sources