1 lettergreep: -er / -est
quick - quicker - quickest
2 lettergrepen (-le, -er, -ow, -y): -er / -est
simple - simpler - simplest
clever - cleverer - cleverest
2 lettergrepen (geen -le, -er, -ow, -y): more / most
famous - more famous - most famous
3 of meer lettergrepen:
popular - more popular - most popular