What part of speech is then in the sentence Then a strong evening breeze whipped tall pines?

In the sentence "Then a strong evening breeze whipped tall pines," the word "then" is an adverb.

Here's why:

* Adverbs modify verbs, adjectives, or other adverbs. They answer questions like "when," "where," "how," or "to what extent."

* In this sentence, "then" tells us when the action of the breeze whipping the pines happened. It modifies the verb "whipped."

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