A. Commonly, adjectives that contain only one syllable or end in 'y' use 'er' to form comparatives and 'est' to form superlatives. For adjectives ending in y, change the 'y' to 'i' before adding the 'er' or 'est'. Example: old – older – oldest / young – younger – youngest / pretty – prettier – prettiest
B. Adjectives with two or more syllables do not change but instead add more to form comparatives and most to form superlatives. Example: respectable – more respectable – most respectable / beautiful – more beautiful – most beautiful
C. Some adjectives have different forms of comparatives and superlatives. Example: good – better – best / bad – worse – worst / little – less – least / much (many) – more – most