1.indefinite article indefinite article 2. (non-specific) one (one); one (kind):
We planted a tree.
We planted a tree. 3. Any one (of similar things) [equivalent to any]:
A gun is dangerous.
A gun is dangerous. 4. Every, every (one):
once a day
once a day
twice a week
twice a week 5. [Used before an abstract noun modified by an attributive] a certain kind:
a happiness that she couldn't quite hide
Her inner joy that she couldn't suppress 6. [Used before a proper noun modified by an attributive, indicating the temporary characteristics or certain attributes of the proper noun]:
It was a cold December.
It was a cold of December. 7. [Used before certain substance nouns] A kind of:
a black tea
A kind of black tea 8. [Used to be embodied, partialized or expressed before abstract nouns of experience] one; a kind of; one time; one time:
They have had a friendship of ten years. 9. [Used before a surname or a noun indicating a political party, group, nation, etc.] A member of...:
a Communist
A Communist Party member 10. [Use Before a person's name, a place name, or a proper noun indicating a date, festival, etc.] a certain (equivalent to a certain):
A Miss Helen called you just now.
A Miss Helen just called you. 11. [Used before proper nouns] A like... [equivalent to one like]:
a Watergate
A Watergate-style scandal 12. [Used to refer to drinks , before certain material nouns of food] a guest; a portion:
a beer
a cup of beer 13. the same (one) [equivalent to the same]:
the people all of a mind
People of the same mind (or people with the same opinions) 14. [Used before images that usually appear together or two matched sets of utensils] a set , a pair, a group:
a cup and saucer
A teacup with a saucer 15. [used before several plural forms of nouns to express the concept of "single"] ：
a falls in the Niagara River
A waterfall on the Niagara River 16. [used before non-specific singular nouns]:
A man falls overboard !
Someone fell into the water! 17. [used before countable collective nouns and certain quantifiers]:
a barracks
A barracks 18.[ Used for names of people or things as typical examples]:
a Cicero in eloquence
A person whose eloquence is as good as Cicero 19. [expression modified with attributive Words such as quantity, time, age, etc. are used together to express a certain attitude or emotion of the speaker]:
Her grandfather is a healthy 90.
Her grandfather is now 90 years old and is still very healthy. healthy.
20. [Used before a trademark name, a person’s name, etc.] A… brand (or model) product; a portrait of…, a sculpture of…; a work of…:
a Boeing 737< /p>
A Boeing 737 aircraft 21. [used before words such as few, little, lot, great many, good many, score, dozen, hundreds, thousands, million, billion and other words to indicate quantity]:
a million thanks
Thank you very much 22. [used before unique things such as world, moon, sun, etc. to express the temporary characteristics or certain attributes of this thing]:
a crescent moon
Crescent moon 23. [used before percentages, cardinal words, or ordinal words starting from third to express fractions]:
a tenth
One-tenth 24. [used before a noun or gerund expressing an action]:
I must get (or have) a wash.
I must get (or have) a wash.
I must get (or have) a wash. 25. [Spoken] [used before some nouns without attributive modification to express procedures]:
I was there for a time.
I stayed there for some time . 26. [Used in negative structures to express emphasis, equivalent to a single]:
never a one
No one (person) 27. [a is generally used in pronunciation with consonant phonemes Before words that start with or start with /h/ sound, such as: a child, a home, a uniform, a eunuch; an is generally used before words that start with a vowel phoneme or a silent h: a?2[?]v.aux.[Spoken language, dialect][used in subjunctive mood, = have]:a?3[?]prep.1.[Spoken language][usually used with nouns, =of]:
a cup a tea
A cup of tea