GRAMMAR ENGLISH ARTICLES

There are two types of articles in the English language: the definite article (the) and the indefinite article (a, an). Try the following practice exercises on definite and indefinite articles. 1

There are two types of articles indefinite a and an or definite the. Their proper use is complex especially when you get into the advanced use of English. Quite often you have to work by what sounds right, which can be frustrating for a learner.
We usually use no article to talk about things in general - the doesn't mean all.
For example:

"Books are expensive." = (All books are expensive.) "The books are expensive." = (Not all books are expensive, just the ones I'm talking about.) 2
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1 http://www.learn4good.com/languages/evrd_grammar/articles.htm
2.http://www.learnenglish.de/grammar/articlestext.htm