音标：[ei]
art. 一
【计】 累加器, 加法器, 地址, 振幅, 模拟, 区域, 面积, 汇编, 组件, 异步
【医】 热力效能
英汉词典
a的短语、例句：
a
(also an ) indef art (The form a is used before consonant sounds and the form an before vowel sounds. Both are used before [C], [Cgp]
or [sing] ns that have not previously been made specific. a用於辅音前, an用於元音前. 两者均用於前文未曾确指的可数单数名词或集合名词之前.)
1 one 一（个）: a man, hotel, girl, committee, unit, U-turn （一个）男人, 旅馆, 姑娘, 委员会, 单位, U形转弯 (Cf 参看 some men, hotels, girls, etc)
an egg, aunt, uncle, hour, X-ray, MP, L-plate （一个）蛋, 姑姑, 叔叔, 小时, X光照片, 下院议员, L字牌 (Cf 参看 some eggs, aunts, uncles, hours, etc)
I can only carry two at a time. 我一次只能携带两个.
There´s a book on the table is that the one you want? 桌子上有一本书--是不是你要的那一本?
2 (used with an abstract n that is restricted by the phrase which follows it 与抽象名词连用时, 该名词後须有限定性词组)
There was still an abundance of food when we arrived. 我们抵达时还有很多食物.
We´re looking for someone with a good knowledge of German. 我们正在找一个精通德语的人.
3 any; every 任何; 每一（个）
A horse is a quadruped. 马是四足动物. (Cf 参看 Horses are quadrupeds.)
An owl can see in the dark. 猫头鹰在黑暗中能看见东西. (Cf 参看 Owls can see...).
4 one single 单一的: He didn´t tell us a thing about his holiday. 他度假的事对我们支字未提.
5 (used with ns followed byof + possess det + n + ´s 与名词+ of +所有格限定词+名词+ ´s连用)
a friend of my father´s, ie one of my father´s friends 我父亲的一个朋友
a habit of Sally´s, ie one of Sally´s habits 萨莉的一种习惯.
6 (used in front of two ns seen as a unit 用於可视为一体的两个名词之前)
a cup and saucer 一副杯碟
a knife and fork 一副刀叉.
7 to or for each; per 每一; 每: 2 a gallon 每加仑2英镑
800 words a day 每天800字 * 50p a pound 每磅50便士.
8 (often derog 常作贬义) person like (sb) 像（某人）的人
My boss is a little Napoleon. 我的老板是个小拿破仑.
9 (used with sb´s name to show that the speaker does not know the person 与某人姓名连用, 表示说话者不认识此人)
Do we know a Tim Smith? 咱们认识一个叫蒂姆?史密斯的人吗?
A Mrs Green is waiting to see you. 有一位格林太太正等著见你.* A Doctor Simpson telephoned. 有一位辛普森医生来过电话.
10 (used to show membership of a class 用以表示一群体中的成员)
My mother is a solicitor. 我母亲是律师.
My father is a Fulham supporter. 我父亲是富勒姆足球队的球迷.
11 painting, sculpture, etc by 由...作的绘画, 雕刻等
The painting my grandfather gave me turned out to be a Constable. 我祖父给我的那幅画原来是康斯塔伯的作品. a NOTE ON USAGE 用法
Note that the sound of the first letter of an abbreviation, not its spelling, determines the form and pronunciation of the article before it 注意用於缩写字前面的冠词, 其词形和读音取决於该缩写字的第一个字母的读音, 而不取决於其书写形式: an MP
an SRN * a UHF radio
the NSPCC * the USA. A abbr 缩写 =
1 ampere(s): 13A, eg on a fuse 13安（如标於保险丝上者）.
2 answer. Cf 参看 Q.
3 (in academic degrees 在学位方面) Associate of
ARCM, ie Associate of the Royal College of Music 皇家音乐学院副研究员. Cf 参看 F2.
A symb 符号 (Brit) (of roads) major （指公路）A级（主干公路）
the A40 to Oxford 通往牛津的A级40号公路
an A-road 一条A级公路. Cf 参看 B.
a