wolf -> wolves life -> lives milieu -> mileus/milieux basis -> bases iris -> irises /irides matrix -> matrixes/matrices phalanx -> phalanxes /phalanges potato -> potatoes photo -> photos graffito -> graffiti tempo -> tempos/tempi aphelion -> aphelia ganglion -> ganglions/ganglia foot -> feet tooth -> teeth hoof -> hoofs/hooves series -> series atlas -> atlases wish -> wishes bacterium -> bacteria medium -> mediums/media genus -> genera stimulus -> stimuli opus -> opuses/opera radius -> radiuses/radii corpus -> corpuses/corporastatus -> statuses/status box -> boxes ferry -> ferries protozoon -> protozoa cherub -> cherubs/cherubim

This site gives you the rules for making nouns plural http://www.paulnoll.com/Books/Clear-English/English-plurals-1.html