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serving concurrently as; holding the additional post of
彼は新しい役職を兼摂することになった。
He was assigned to serve concurrently in a new position.
彼女は管理職を兼摂している。
She is holding the additional post of a managerial position.
兼摂することで業務が増えた。
By serving concurrently, her workload increased.