What is the adverb in sentence By time I got to school bell had already rung?

The adverb in the sentence "By the time I got to school, the bell had already rung" is "already".

Here's why:

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

* "Already" tells us about the time of the action. It indicates that the bell rang before the speaker arrived at school.

Let me know if you have any other sentences you'd like to analyze!