english question

when do you use "a" and "the"? What is the different between both A and The?

[Hi_there_Carl]

The is used to refer to specific or particular nouns; a/an is used to modify non-specific or non-particular nouns. We call the the definite article and a/an the indefinite article.


For example, if I say, "Let's read the book," I mean a specific book. If I say, "Let's read a book," I mean any book rather than a specific book.


Here's another way to explain it: The is used to refer to a specific or particular member of a group. For example, "I just saw the most popular movie of the year." There are many movies, but only one particular movie is the most popular. Therefore, we use the.


"A/an" is used to refer to a non-specific or non-particular member of the group. For example, "I would like to go see a movie." Here, we're not talking about a specific movie. We're talking about any movie. There are many movies, and I want to see any movie. I don't have a specific one in mind.
Let's look at each kind of article a little more closely.
Indefinite Articles: a and an

"A" and "an" signal that the noun modified is indefinite, referring to any member of a group. For example:

• "My daughter really wants a dog for Christmas." This refers to any dog. We don't know which dog because we haven't found the dog yet.
• "Somebody call a policeman!" This refers to any policeman. We don't need a specific policeman; we need any policeman who is available.
• "When I was at the zoo, I saw an elephant!" Here, we're talking about a single, non-specific thing, in this case an elephant. There are probably several elephants at the zoo, but there's only one we're talking about here.

Remember, using a or an depends on the sound that begins the next word. So...

• a + singular noun beginning with a consonant: a boy; a car; a bike; a zoo; a dog
• an + singular noun beginning with a vowel: an elephant; an egg; an apple; an idiot; an orphan
• a + singular noun beginning with a consonant sound: a user (sounds like 'yoo-zer,' i.e. begins with a consonant 'y' sound, so 'a' is used); a university; a unicycle

If the noun is modified by an adjective, the choice between a and an depends on the initial sound of the adjective that immediately follows the article:

• a broken egg
• an unusual problem
• a European country (sounds like 'yer-o-pi-an,' i.e. begins with consonant 'y' sound)

Remember, too, that in English, the indefinite articles are used to indicate membership in a group:

• I am a teacher. (I am a member of a large group known as teachers.)
• Brian is an Irishman. (Brian is a member of the people known as Irish.)
• Seiko is a practicing Buddhist. (Seiko is a member of the group of people known as Buddhists.)

Definite Article: the

The definite article is used before singular and plural nouns when the noun is specific or particular. The signals that the noun is definite, that it refers to a particular member of a group. For example:
"The dog that bit me ran away." Here, we're talking about a specific dog, the dog that bit me.
"I was happy to see the policeman who saved my cat!" Here, we're talking about a particular policeman. Even if we don't know the policeman's name, it's still a particular policeman because it is the one who saved the cat.
"I saw the elephant at the zoo." Here, we're talking about a specific noun. Probably there is only one elephant at the zoo.
Count and Noncount Nouns

The can be used with noncount nouns, or the article can be omitted entirely.

• "I love to sail over the water" (some specific body of water) or "I love to sail over water" (any water).
• "He spilled the milk all over the floor" (some specific milk, perhaps the milk you bought earlier that day) or "He spilled milk all over the floor" (any milk).

"A/an" can be used only with count nouns.

• "I need a bottle of water."
• "I need a new glass of milk."

Most of the time, you can't say, "She wants a water," unless you're implying, say, a bottle of water.
Geographical use of the

There are some specific rules for using the with geographical nouns.
Do not use the before:

• names of most countries/territories: Italy, Mexico, Bolivia; however, the Netherlands, the Dominican Republic, the Philippines, the United States
• names of cities, towns, or states: Seoul, Manitoba, Miami
• names of streets: Washington Blvd., Main St.
• names of lakes and bays: Lake Titicaca, Lake Erie except with a group of lakes like the Great Lakes
• names of mountains: Mount Everest, Mount Fuji except with ranges of mountains like the Andes or the Rockies or unusual names like the Matterhorn
• names of continents (Asia, Europe)
• names of islands (Easter Island, Maui, Key West) except with island chains like the Aleutians, the Hebrides, or the Canary Islands

Do use the before:

• names of rivers, oceans and seas: the Nile, the Pacific
• points on the globe: the Equator, the North Pole
• geographical areas: the Middle East, the West
• deserts, forests, gulfs, and peninsulas: the Sahara, the Persian Gulf, the Black Forest, the Iberian Peninsula

Omission of Articles

Some common types of nouns that don't take an article are:

• Names of languages and nationalities: Chinese, English, Spanish, Russian
• Names of sports: volleyball, hockey, baseball
• Names of academic subjects: mathematics, biology, history, computer science
  

[rewboss]

Short answer:

If say "a cat", then I assume that you do not yet know which cat I am talking about:

"There is a cat in our garden."

But if I say "the cat", then I assume that you already know which cat I am talking about:

"There is a cat in our garden. The cat [meaning: the cat I mentioned in my last sentence, the cat I am talking about] is looking at our goldfish pond."

Or perhaps:

"The cat [meaning: our cat -- we only have one] is in the garden [meaning: our garden]."

"The ginger cat [meaning: you know which cat, the one from that house at the end of our street] is in our garden."

Also, note the following:

"A queen is the wife of a king." [It doesn't matter which queen.]

"The queen is not amused." [You know which queen I mean: it's the queen of our country.]

As Hi_there_Carl says, there are more rules than that. But this is the basic rule to remember.