What part of speech is twice?

"Twice" can be two different parts of speech, depending on how it's used:

* Adverb: When it modifies a verb, adjective, or another adverb.

* Example: "He ate twice as much as I did." (modifies the verb "ate")

* Determiner: When it means "two times" or "two instances."

* Example: "I've been to Paris twice." (indicates two occasions)

Let me know if you'd like more examples!