Adjectives and adverbs: comparison, modes of action, and frequency

An adjective describes a noun (a slow train). An adverb often describes a verb (He drives slowly).

Making adverbs

Many: adjective + -ly: quick → quickly, careful → carefully. Exceptions: good → well, fast → fast, hard → hard (“with effort” — not hardly, which means “almost not”).

Comparative and superlative

Short adjectives: tall → taller → the tallest
-y: happy → happier → the happiest
Long: more interesting → the most interesting
Irregular: good/better/best, bad/worse/worst, far/further/furthest (also farther)

This film is better than that one.
She is the tallest in the class.
as ... as: He is as old as me.

Frequency: always, usually, often, sometimes, rarely, never — before the main verb, after be: She often calls. · He is never late.