一[yī] 基本解释：
新英汉大词典：
- 一[yī]
- 数词- （最小的正整数） one:
one hundred kilograms;一百公斤
a book;一本书
- （同一） same:bitter gourds from the same vine; people with a similar bitter past;一根藤上的苦瓜
the same thing;一码事
- （另一） also; otherwise:Merbromin is also known as mercurochrome.汞溴红一名红汞。
- （全; 满） whole; all; throughout:the whole winter; all winter; throughout the winter;一冬
one's face covered with dust;一脸的土
- （专一） concentrated; wholehearted:heart and soul; wholeheartedly一心一意
- （单一; 唯一） single; alone; only one:hit the target with a single shot;一枪就打中了目标
Can you manage all by yourself?你一个人行吗?
- （表示动作是一次或短暂的）:wait a bit;等一等
give a cough;咳一声
- （每一）each; per; every time:four groups with five people in each;四个小组，一组五人
tree meals a day;一日三餐
- （用在动词或动量词前面，表示先做某个动作，下文说明动作结果）:get over in one jump;一跳跳了过去
This explanation of his restored our confidence.经他这么一说，大家又都有信心了。
- 副词- （一旦; 一经） once; as soon as:
Once seen, never forgotten.一见不忘。
You will be clear about it as soon as you look at it.你一看就会清楚的。
- 助词- （用在某些词前加强语气）:
be as easy as catching a turtle in a jar;一似瓮中捉鳖
To think that things should have come to such a pass!事态之严重一至于此!
- 名词- {音} （中国民族音乐音阶上的一级） a note of the scale in gongchepu （工尺谱），corresponding to 17 in numbered musical notation
例句与用法：
There's a good A-road going North -- the A1.
He lives in a cosy little room.
He took my ace with a low trump.
It takes a lot of labor to build a railway.
Would you do me a favor?