fixed shift造句

since the human power of this center is limited that service volunteers provide service by regular arrangement of fixed shift, if the volunteer could not be present for duty by some reason, may ask other volunteers to act the duty in advance, and if no acting volunteer is found, may report the leader for help
本馆人力有限，义务服务员系采固定排班方式服务，如因故不克到勤服务，可事先商请其他义务服务员代班，若无法自行觅得代班者，可向该队小长报告寻求协助。
It's difficult to find fixed shift in a sentence. 用fixed shift造句挺难的