a
indefinite article /ə/, strong form /eɪ/
/ə/, strong form /eɪ/
(also an
The form a is used before consonant sounds and the form an before vowel sounds. When saying abbreviations like ‘FM’ or ‘UN’, use a or an according to how the first letter is said. For example, F is a consonant, but begins with the sound /e/ and so you say: an FM radio . U is a vowel but begins with /j/ and so you say: a UN declaration . /ən/, strong form /æn/
/ən/, strong form /æn/
)- used before countable or singular nouns referring to people or things that have not already been mentioned
（用于可数名词或单数名词前，表示未曾提到的）一（人、事、物） - a man/horse/unit
一个人；一匹马；一个单位 - an aunt/egg/hour/X-ray
一位姑母；一枚鸡蛋；一小时；一张 X 光片 - I can only carry two at a time.
我一次只能带两个。 - There's a visitor for you.
有位客人找你。 - She's a friend of my father's (= one of my father's friends).
她是我父亲的朋友。
- a man/horse/unit
- used to show that somebody/something is a member of a group or profession
（表示为某一群体或职业中的一员） - Their new car's a BMW.
他们的新轿车是辆宝马。 - She's a Buddhist.
她是佛教徒。 - He's a teacher.
他是教师。 - Is that a Monet (= a painting by Monet)?
那是莫奈的画吗？
- Their new car's a BMW.
- any; every
任何一；每一 - A lion is a dangerous animal.
狮子是猛兽。
- A lion is a dangerous animal.
- used before uncountable nouns when these have an adjective in front of them, or phrase following them
（用于前有形容词或后有短语的不可数名词前） - a good knowledge of French
精通法语 - a sadness that won’t go away
挥之不去的悲愁
- a good knowledge of French
- used in front of two nouns that are seen as a single unit
（用于视为一体的两个名词之前） - a knife and fork
一副刀叉
- a knife and fork
- used instead of one before some numbers
（用于某些数字前，代替 one） - A thousand people were there.
那里有一千人。
- A thousand people were there.
- used when talking about prices, quantities and rates
（用于价格、数量、比率等）一，每一 - They cost 50p a kilo.
这些东西一公斤 50 便士。 - I can type 50 words a minute.
我每分钟能打 50 个单词。 - He was driving at 50 miles an hour.
当时他正以每小时 50 英里的速度驾车。
- They cost 50p a kilo.
- a person like somebody
像（某人）的人；…式的人物 - She's a little Hitler.
她是个小希特勒。
- She's a little Hitler.
- used before somebody’s name to show that the speaker does not know the person
（用于某人姓名前，表示说话者不认识此人）有个 - There's a Mrs Green to see you.
有位格林太太要见你。
- There's a Mrs Green to see you.
- used before the names of days of the week to talk about one particular day
（用于一星期中某天的名称前，表示具体某一天） - She died on a Tuesday.
她是在某个星期二去世的。
- She died on a Tuesday.
词源Middle English: weak form of Old English ān ‘one’.