obtainable (adj.) obtain (v.) obtain vt.获得；得到vi.流行；通用；存在obstructive (adj.) obstructionist (n.) obstructionism (n.) obstruction (n.) obstruct (v.) obstreperous (adj.) obstipation (n.) obstinate (adj.) obstinance (n.) obstinacy (n.) obstetrics (n.) obstetrician (n.) obstetric (adj.) obstacle (n.) obsolete (adj.) obsolescent (adj.) obsolescence (n.)