*** Using “a” and “an” Before Words ***
The Rule
The rule states that “a” should be used before words that begin
with consonants, while “an” should be used before words
that begin with vowels
Notice, however, that the usage is determined by the pronunciation
and not by the spelling, as many people wrongly assume
"You should say, therefore, “an hour
(because hour begins with a vowel sound)
(and “a history” (because history begins with a consonant sound
Similarly you should say “a union” even if union begins with a “u.” That
is because the pronunciation begins with “yu”, which
is a consonant sound
with consonants, while “an” should be used before words
that begin with vowels
Notice, however, that the usage is determined by the pronunciation
and not by the spelling, as many people wrongly assume
"You should say, therefore, “an hour
(because hour begins with a vowel sound)
(and “a history” (because history begins with a consonant sound
Similarly you should say “a union” even if union begins with a “u.” That
is because the pronunciation begins with “yu”, which
is a consonant sound
Abbreviations
Deciding which version you should use with abbreviations is the tricky
part. First of all you need to understand if the abbreviation is pronounced
.as a single word or letter by letter
"While we say “a light-water reactor,” the abbreviation is “an LWR
Similarly, you should use “an NBC reporter”
(because “NBC” is pronounced “enbisi”)
(and “a NATO authority” (because “NATO” begins with a “ne” sound
part. First of all you need to understand if the abbreviation is pronounced
.as a single word or letter by letter
"While we say “a light-water reactor,” the abbreviation is “an LWR
Similarly, you should use “an NBC reporter”
(because “NBC” is pronounced “enbisi”)
(and “a NATO authority” (because “NATO” begins with a “ne” sound
تم بإذن الله
م/ن
وباأإأإقــة ورد 
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