Just like how verbs, adverbs or adjectives in a list must agree. Descriptive words are easy to replace with wordy phrases, and test writers will try to trip you up by including a verb or phrase among a list of adjectives or adverbs:

On the morning of his fourth birthday, Johnny was giggly, energetic, and couldn't wait for the party to begin.

If you read through the sentence quickly, it might sound acceptable. However, the list includes one item that doesn't belong:

This looks to be a list of adjectives until you reach the third item in the list: it's not an adjective, it's a verb! The "list of adjectives" won't be complete until the last item falls into step with the others:

This example replaces the verb phrase couldn't wait with the descriptive phrase very eager — which indeed includes an adjective.

Watch for consistency in item type as well as consistency of form.

Incorrect: On the morning of his fourth birthday, Johnny was giggly, energetic and couldn't wait for the party to begin.

Correct: On the morning of his fourth birthday, Johnny was giggly, energetic and very eager for the party to begin.

Lists of Verbs and Parallel Constructions

Comparisons Between Pronouns