a-gen-cy, va-can-cy, ca-den-cy, la-ten-cy (tense vowel: like hay, may)
ab-sen-cy (consonant cluster gets split across the syllables): lax vowel like hat
re-gen-cy, de-cen-cy (tense)
ten-den-cy (lax, consonant cluster nd gets split)
po-ten-cy, co-gen-cy (tense)
if there is a gibberish word like pok-ten-cy, you see a lax vowel like got, cot.
you can see this patterns that got vowel digraphs.
effi-'ca-cious (tense)
con-scious (lax thanks to the consonant cluster)
Many 2 syllable words have similar structure:
a-nus, sta-tus, ma-gus, hi-a-tus, bo-nus, lo-cus (tense)
mag-nus (lax, consonant cluster gn)
na-tion (tense)
fraction (lax, thanks to ct)
pa-gan, rea-gan,ga-gan, hi-a-tus