If the verb ends with an e, we add only "d" to it.
bake baked
replace replaced
If the verb ends with consonant + y, we drop the "y" and add "ied" to it.
(consonant = all letters but a, e, i, o, u)
cry cried
terrify terrified
If the verb ends with vowel + y, we add only "ed" to it.
(vowel = a, e, i, o, u)
play played
obey obeyed
If the verb has only one syllable and it ends with: consonant + vowel + consonant,
and the last consonant is not w, x, y we double the last consonant and add "ed" to it.
drop dropped
skip skipped
Practice Regular Verbs
Turn the verbs into their past form.
Results
We add "ed" to most of the verbs.
work worked
cook cooked
If the verb ends with an e, we add only "d" to it.
bake baked
replace replaced
If the verb ends with consonant+y, we drop the "y" and add "ied" to it.
(consonant = all letters but a, e, i, o, u)
cry cried
terrify terrified
If the verb ends with vowel+y, we add only "ed" to it.
(vowel = a, e, i, o, u)
play played
obey obeyed
If the verb has only one syllable and it ends with consonant+vowel+consonant,
and the last consonant is not w, x, y we double the last consonant and add "ed" to it.
worked 
worked