- object
- objective
- oblige
- obscure
- obsolete
- obstinate
- occasion
- occupy
- occur
- odd
- offend
- offence
- offset
- omit
- opaque
- optimistic
- option
- orient
- origin
- ornament
- orthodox
- outline
- overflow
- overhaul
- overhear
- overlap
- off and on
- overtake
- on a large scale
- overthrow
- on a small scale
- overwhelm
- on account of
- on average
- on behalf of
- on board
- on business
- on condition that
- on duty
- on earth
- on fire
- on foot
- on guard
- on hand
- on occasion
- on purpose
- on sale
- on schedule
- on second thoughts
- on the contrary
- on the ground of
- on one hand
- on the other hand
- on the point of
- on the road
- on the spot
- on the whole
- on time
- once again
- once for all
- once in a while
- out of breath
- out of control
- out of date
- out of doors
- out of order
- out of place
- out of practice
- out of sight
- out of the question
- out of touch
- over and over
大学英语2011考研英语核心单词单词大全〔O 〕课程包含72个英语单词词汇。