operative

adj. （计划等）实施中的，生效的

opencast, opener, opening, opening night, opening-time, openly, openness, opera, opera-glasses, opera-house, operable, operate, operatic, operatically, operating system, operating-table, operating-theatre, operation, operational, operations room, operator, operetta, ophthalmic, ophthalmic optician, ophthalmologist, ophthalmology, ophthalmoscope, opiate, opine, opinion, opinion poll, opinionated, opium, opossum, opp, opponent, opportune, opportunely, opportunism, opportunist,