used when mentioning someone or something for the first time in a text or conversation [用于第一次提及某人或某事物]有个,某个,一个。 比较 the a man came out of the room. 一个男人走出了房间。 it has been an honour to have you. 你能来真是荣幸。 we need people with a knowledge of languages. 我们需要有语言知识的人。 ■used with units of measurement to mean one such unit [与度量单位连用,表示一个单位]一 a hundred. 一百。 a quarter of an hour. 一刻钟。 ■[with negative]one single; any 一个,任何一个 I simply haven't a thing to wear. 我简直没有衣服可穿。 ■used when mentioning the name of someone not known to the speaker [用于提及说话者不认识的人]某一个 a Mr Smith telephoned. 有个史密斯先生打电话来过。 ■someone like (the name specified) [与具体人名连用]像…的人 you're no better than a Hitler. 你就像个希特勒。
used to indicate membership of a class of people or things [用于表示某一类人或事物]一个,一 he is a lawyer. 他是律师。 this car is a BMW. 这是辆宝马车。
in, to, or for each; per (used when expressing rates or ratios) [用于表示速度或比率]每 typing 60 words a minute. 每分钟打60个词。 a move to raise petrol prices by 3p a litre. 将汽油价格每升提高三便士的动议。
语源
Middle English : weak form of Old English ān 'one'
用法
On the question of using a or an before words beginning with h, see usage at an
a2 abbreviation for
■(in travel timetables) arrives [用于旅行时刻表]。 同 arrives Penzance a 0915. 9点15分到达彭赞斯。 ■[in combination](in units of measurement) atto- (10-18) (度量单位)。 同 atto- ■(Brit)(with reference to sporting fixtures) away (英)(比赛的安排)。 同 away March 15 Sheffield United (a). 设菲尔德联队将于3月15日在客场举行比赛。 Latin ■(used before a date) before 在…之前(用于日期之前) a1200. 1200年前。