用法:
1 flock (of geese) （鹅）群.

用法:
2 (fig 比喻) group of noisy or talkative people 一群（喧哗或多话的人）:
a gaggle of tourists, schoolchildren, etc 一群喧闹的游客, 小学生等.

• not to say(not to speak of)
• not to Say(to Say nothing of)
• not within one's power(out of one's power)
• not without advantage(with advantage)
• notable(noticeable)
• note(notice)
• nothing but(nothing else but)
• nothing else than(nothing less than)
• nothing(no thing)
• notorious(well-known)
• now and then(then and there)
• nowaday （ s ）(at the present time)
• O (oh)
• object(have no objection to)
• object(object to)
• oblige sb by doing sth(oblige sb to do sth)
• observance(observation)
• occupant(occupier)
• of a day(of the day)
• of a kind(of the kind)
• of a sort(of the sort)
• of age(of an age)
• of age(of one's age)
• of moment(of the moment)
• of no avail(to no avail)