have at fingers' ends 同义词
1 精通
great hot wise savvy proficient adept acquainted front-line well-versed conversant versed up knowledge grip proficiency mastery familiarity mastership conversance know understand master acquaint be a master of have at finger tips au fait have at fingers' tips have at fingertips be adept in be learned in be at home in have at the tips of fingers be proficient in have a light hand with on to
2 熟知
aware known well-informed knowledge familiarization have at finger tips have at fingers' tips have at fingertips be clued up know backward in the picture
3 手头有…可利用