observation

n.观察，注意；观察力；评论，意见

obnoxious, obnoxiously, obnoxiousness, oboe, oboist, obscene, obscenely, obscenity, obscur, obscure, obscurely, obscurity, obsequies, obsequious, obsequiously, obsequiousness, observable, observance, observant, observantly, observation car, observation post, observatory, observe, observer, observing, obsess, obsessed, obsession, obsessional, obsessive, obsessively, obsolescence, obsolescent, obsolete, obssess, obstacle, obstacle race, obstetric, obstetrician,