Final answer:
The adverb, comparative and superlative forms of the adjectives cheap, heavy, fast, bad, serious, and wonderful are respectively cheaply, more cheaply, most cheaply; (heavily, more heavily, most heavily); fast, faster, fastest; badly, worse, worst; seriously, more seriously, most seriously; and (wonderfully, more wonderfully, most wonderfully).
Step-by-step explanation:
To answer your question regarding the adverb, comparative, and superlative forms of the given adjectives:
1. For the adjective cheap, the adverb form is cheaply, the comparative adverb would be more cheaply, and the superlative adverb would be most cheaply.
2. The adjective heavy does not easily convert to an adverb in relation to weight; however, if considered in terms of gravity or pressure, it might be heavily, with the comparative being more heavily, and the superlative being most heavily.
3. For the adjective fast, the adverb is the same, fast (e.g., 'run fast'), with the comparative being faster and the superlative being fastest.
4. The adjective bad becomes the adverb badly, with the comparative being worse, and the superlative being worst.
5. With serious, the adverb is seriously, the comparative is more seriously, and the superlative is most seriously.
6. Lastly, wonderful as an adjective typically does not have an adverb form, but you could use wonderfully in a different context, with the comparative form being more wonderfully and the superlative being most wonderfully.