3.
[:alpha:] can also be specified as.

4.
How many functions does PHP offer for searching strings using POSIX style regular expression?

5.
What will be the output of the following PHP code?
<?php
$username = "jasoN";
if (ereg("([^a-z])",$username))
  echo "Username must be all lowercase!";
else
  echo "Username is all lowercase!";
?>