Read perlrequick, perlre,perlrecharclass 

1.Read how to match a string.
2.Read How to group a matched string
Ex, 
my $str="a apple";
$str =~(s/a(\s+[aeiou].+)/an\1/g);
print $str

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In reply to Re: Perl pattern matching question by vinoth.ree
in thread Perl pattern matching question by MadhAric

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