1. short A/Adv: Add “er” after them: shorter, longer, higher, . Some exceptions: end with “y” change into “I” then add “er”: lovelier, prettier, happier, end by consonant preceded with vowel, double consonant : thinner, fatter, slimmer, . end with “w, er, t” add only “er” : slower, cleverer, quieter, smarter,