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to be fit (for a role); to be qualified (for); to be equal (to a task); to be able to fulfill one's duties (as)
この仕事は体力がないと勤まらないだろう。
This job probably cannot be done without physical stamina.
責任感のない人には班長は勤まらない。
Someone without a sense of responsibility cannot serve as group leader.
厳しい環境でも勤まる人材を育成する必要がある。
There is a need to develop personnel who can perform even in harsh conditions.