* 1 syllable: -er than / the -est
example: strange - strang
er than - the strang
est
* 2 syllables ending in -le, -er, -ow, -y: -er than / the -est
example: simple - simpler than - the simplest
* 2 syllables not ending in -le, -er, -ow, -y: more /most
example: careful - more careful than - the most careful