formula-formulae, formulas, alumna-alumnae, vertebra-vertebrae, vertebras, focus-foci, focuses, cactus-cacti, fungus-fungi, funguses, bacterium-bacteria, curriculum-curricula, dictum-dicta, datum-data, criterion-criteria, phenomenon- phenomena, dogma-dogmata, stigma-stigmata, basis- bases, crisis-crises, analysis- analyses, hypothesis-hypotheses