 If the word ends in a consonant, add -er (quick becomes quicker).
 With words of one syllable with a short vowel sound and ending with a single consonant, double the consonant and add -er (sad becomes sadder).
 With words of one syllable ending in -l, you normally do not double the l, but cruel becomes crueller.
 If it ends in ‘e’ add -r (late becomes later).
 If it ends in ‘y’, change the ‘y’ to an ‘i’ and add -er (happy becomes happier).
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