Use the -est to indicate the superlative of one-syllable adjectives and adverbs as well as two-syllable adjectives ending in -y.
- He’s the fastest man alive.
- That’s the funniest clown I’ve ever seen.
- Ben works the hardest of them all.
Use the best or the worst as the superlative of good or well.
- This is the best deal I can offer you.
- That was the best time I’ve ever had.
- It was the worst dinner I’ve ever cooked.
- I like this one (the) best.
Use the most + adjective/adverb to indicate the superlative of longer adjectives and adverbs.
- He’s the most wonderful man I’ve met.
- That was the most difficult exam I’ve ever taken.
- Chris sings the most beautifully of them all.