GRAMMAR - Articles

In English we can distinguish two kinds of nouns:

- Countable nouns have a singular and a plural form; they can be counted with numbers:

	A computer is a machine that performs computations according to instructions.
	There are eighteen computers in our classroom.

- Uncountable nouns only have a singular form, and they can't be counted with numbers:

	I need some information about my SD card.
	10,000 pieces of information are exchanged per second on Facebook.

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In English there are three kinds of articles:

For countable nouns only:
•	We use a / an with countable nouns in the singular: a computer, a printer
	We use an is used if the next word begins with a vowel: an old computer
	We use a when a word that begins with "u" is pronounced with the semiconsonant /j/: a unix system

• We use a / an when we mention something for the first time (it is new information):

	OK, class, everybody sit down in front of a computer.

• We use the (with countable or uncountable nouns) when we mention something again:

	Now switch on the computer, please.
	The information is now in the RAM memory.

• We use the zero article (no article, represented by Ø) to talk about things in general, for example to define or describe things; if they are countable, we normally use them in the plural:

	Ø Information is power.
	Ø Computers are getting more and more powerful all the time.

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When we talk about something in general there are several possibilities for countable nouns:

	Technically, a computer is a programmable machine.
	The computer is one of the most powerful innovations in human history.
	Computers are incredibly fast, accurate, and stupid.

To talk about an uncountable noun in general, we always use the zero article:

	Ø Information is not the same as Ø data.