What is the adverb in sentence He seldom did poorly on tests?

The adverb in the sentence "He seldom did poorly on tests" is seldom.

Here's why:

* Adverbs modify verbs, adjectives, or other adverbs. In this case, "seldom" modifies the verb "did".

* "Seldom" tells us how often he did poorly on tests. It indicates that he did poorly infrequently.

Let me know if you'd like to try another sentence!