Most adjectives and adverbs have three forms: positive, comparative, and superlative. You usually form the comparative and superlative of one- or two-syllable adjectives by adding -er and -est: short, shorter, shortest. With some two-syllable adjectives, longer adjectives, and most adverbs, use more and most (or less and least): scientific, more scientific, most scientific; elegantly, more elegantly, most elegantly. Some short adjectives and adverbs have irregular comparative and superlative forms: good, better, best; badly, worse, worst.