Nouns, verbs and adjectives:

Spelling Rule: nouns and verbs

Just add (s) to the end of the word
a) to make plural nouns
b) to form the 3rd person singular of the present simple tense

Exceptions:

If the word ends in : s, ss, sh, ch, x, o, z = es

bus = buses       wash = washes           miss = misses
box = boxes       church = churches      potato = potatoes
go = goes          tomato = tomatoes

If the word ends in : f, fe remove f, fe and add ves

wife = wives     calf = calves     leaf = leaves  yourself = yourselves
except:
beliefs, chiefs, dwarfs, griefs, gulfs, proofs, roofs


Words ending in y:

If the word ends in : consonant + y

y changes to ie before ending s:
baby = babies       story = stories      spy = spies        sky = skies
study = studies     worry = worries    try = tries          apply = applies

y changes to i before ending ed:
study = studied         worry = worried       try = tried        apply = applied

y changes to i before ending ly:
happy = happily        easy = easily            lucky = luckily

y changes to i before endings er and est:
happy = happier, happiest         easy = easier, easiest  
lucky = luckier, luckiest

y doesn't change before ing:
study = studying         try = trying       apply = applying