1. The correct adverb for "regular" is "regularly". The adverb "regularly" is formed by adding the suffix "-ly" to the adjective "regular". Adverbs ending with "-ly" describe how an action is done.
2. The correct adverb for "hard" is also "hard". The adjective "hard" does not require any changes to become an adverb. It already describes how an action is done, so it does not need the "-ly" suffix.
3. The correct adverb for "happy" is "happily". Similar to "regularly", the adverb "happily" is formed by adding the suffix "-ly" to the adjective "happy". This adverb describes how an action is done.
In summary, the correct adverbs are:
1. regularly
2. hard
3. happily
2. The correct adverb for "hard" is also "hard". The adjective "hard" does not require any changes to become an adverb. It already describes how an action is done, so it does not need the "-ly" suffix.
3. The correct adverb for "happy" is "happily". Similar to "regularly", the adverb "happily" is formed by adding the suffix "-ly" to the adjective "happy". This adverb describes how an action is done.
In summary, the correct adverbs are:
1. regularly
2. hard
3. happily