(can make oneself)usefulin some kind of work; capable of one specific job;expert in some kind of work; have the expertise in one speciality; proficiency in a particular field;skilful (/well-versed) in one line ❍ 这些人员中，凡有～而无严重的反动行为或严重的劣迹者，人民政府准予分别录用。(《毛泽东选集》1347) The People’s Government will permit the employment of those among them who can make themselves useful in some kind of work and have not committed any grave reactionary act or other flagrant misdeed./……奖励他们的～，一滴之功。(《中国农村的社会主义高潮》300) …and their every skill and merit were awarded.
一技之长
proficiency in a particular line or field;professional skill;master of sth
一技之长yī jì zhī chánɡ
技：技能、本领；长：专长。指有某种特长。specialty, skilful in one field, well versed in one line, a single skill