حرف تعریف معین و حرف تعریف نا معین
Indefinite and definite articles, such as “a”, “an” and “the”, describe and modify nouns. Articles and niggling little words known as determiners and quantifiers convey general and specific information. Articles tell the reader what you’re talking about and how much there is. Adults and advanced ESL students can run into many challenging situations where abstract and collective nouns make it difficult to decide whether to use “a”, “an” or “the.” In fact, article-related errors are one of the most frequent grammatical mistakes among ESL students representing 11% of all errors.