In the sentence "A long time ago, there lived a beautiful princess," what part of speech is the word "ago"?

I believe it acts as an adjective describing the word "time." If the structure of the sentence is changed to:

Long ago, there lived a princess.

I think then it would be an adverb describing "lived."

I would wait for further confirmation on that from someone else, but that's my initial thought.

"a long time ago" is an adverb phrase telling when.

To determine the part of speech of a word, we need to consider its function in the sentence. In the sentence "A long time ago, there lived a beautiful princess," the word "ago" modifies the noun phrase "a long time." It expresses a specific point in the past. Therefore, "ago" is functioning as an adverb in this sentence.

To identify the part of speech of a word, you can follow these steps:
1. Determine the word's function in the sentence.
2. Identify any modifiers or qualifiers (e.g., adjectives, adverbs) that describe the word.
3. Consult a reliable dictionary or grammar resource for further clarification, as some words can have multiple functions or be part of different word classes depending on the context.