Unit 1 Short Vowel a : -ad, -ag, -am
Unit 2 Short Vowel a : -an, -ap, -at
Unit 3 Short Vowel i : -ig, -in, -ip
Unit 4 Short Vowel i : -id, -it, -ix
Unit 5 Review : unit 1 ~ unit 4
Unit 6 Short Vowel U : -ug, -un, -ut
Unit 7 Short Vowel U : -ub, -ud, -um, -up
Unit 8 Short Vowel e : -ed, -en, -et
Unit 9 Short Vowel o : -og, -ot, -ox
Unit 10 Review : unit 6 ~ unit 9