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There are four suffixes for the passive form which are "-이-", "-히-","-리-", "-기-", but we seldom use passive forms. In most cases active forms are preferred.
You can get some more at..
http://www.koreanwikiproject.com/wiki/?title=Passive_form and
http://www.talktomeinkorean.com/lessons/l6l21/
\^o^/