... especially article a/ an are rather a challenge for learners and for us also. Because of the complexities in using, article a/ an may lead the misunderstanding and difficulties to learners. Therefore, ... an umbrella, an orange, an F A/ an has an indefinite meaning (person, animals or thing referred to may be not know to the listener or readers, so A/ an has the sense of any or I can’t ... vocabulary but also its grammar. The learners, in fact, have to meet grammatical problem very much such as: tense, verb, adj…Particularly articles. The correct use of articles a/ an...