eregreplace() and regular expressions...

Greetings, Regular Expressions = hmmm <scratching ones head...> I have a string that contains "it is very important to leave all words larger than three characters" I want only the words that contain 4 or more characters. Can I replace them with some type of statement like $string = ereg_replace("[^.{1}$]", "", "$string"); // 1 char word $string = ereg_replace("[^.{2}$]", "", "$string"); // 2 char word $string = ereg_replace("[^.{3}$]", "", "$string"); // 3 char word Note the above returns an empty value. <scratching my head> Thanks