1, officer n. official, clerk; staff; officer
2, official n. official, administrative officer a. official, official, formal
3, offset n. branch, compensation v. offset, compensation
4, offspring n. Descendants, offspring; results, products
5, often ad. often, often, usually
6, oil n. oil, petroleum v. lubricate...; oil, oil
7, okay a. (okey, OK, O.K.) Okay, OK, good n. Agree
8, old a. Old;...year-old; long time, old; past
9, omit v. Omit, delete; omit, ignore
10, on a. Connect prep. on...; close to ad. forward, continue
11, once ad. once, once conj. once (once)... n. once
12, one num. one pron. one (only) (indicating that the substitution can be counted something)
13, oneself pron. [reflexive pronoun] oneself; personally, myself
14, onion n. onion
15, only ad. only, just a. only conj. but, but
16, onto prep. in... above; to... above
17, opaque a. Opaque (light); difficult to understand, obscure
18, open n. open, outdoor a. open, open v. open
19, opening n. open, open , start, vacancy, opportunity a. start, opening
20, opera n. opera
21, operate v. operate, run, start, function, operate
22, operation n. run, start, operate, operation, operation, Operation
23, operational a. Operation, operation, function, business
24, operator n. operator, (telephone) operator
25, opinion n. opinion, opinion, proposition
26, opponent n. opponent, opponent, Opponent a. Opposite, confrontation
27, opportunity n. Opportunity
28, oppose v. Oppose, make opposition, make confrontation, make relative
29, opposite a. Opposite, relative, opposite n. Opposite
30, oppress v. Oppression, suppression
31, opt vi. choice, choice
32, optical a. eye, vision; optical
33, optimistic a. optimism
34, optimum a. most suitable n. most suitable (condition)
35, option n. Choice (right), [Business] The privilege of choosing to buy or sell
36, optional a. Optional, arbitrary, non-mandatory
37, or conj. Or, or (indicating choice); that is, approximately; otherwise
38, oral a. oral
39, orange n. tangerine, tangerine, orange
40, orbit n. orbit v. (make) line along the track
41, orchard n. orchard, all the fruit trees in the orchard, Meili baseball field
42, orchestra n. .Orchestra
43, order n. order; order; neat; order form; level v. customization, order
44, orderly a. neat, orderly, organized n. orderly
45, ordinary a. ordinary, ordinary of, ordinary; mediocre
46, ore n. ore, ore
47, organ n. organ; institution, mechanism; organ
48, organic a. organ; organic; organism
49, organism n. organism, organism
50, organization n. (organization) organization, group, institution
