Careful checks must be made before the factory commences operation.工厂开始运营之前必须进行仔细的检测。Their contract commences in January.他们的合同从一月份起生效。This Agreement commences on the date of signature hereof.本协议自签字之日起生效。The course commences with a one week introduction to Art Theory.这门课程开始先是一周的艺术理论导论。