Well an adverb clause is a dependent clause used as an adverb in a sentence to indicate time, place, condition, reason, purpose, result, etc.
Here are some examples of how it might be used:
-"Linda scrubbed the floor until her arms ached." Here the adverb clause describes how Linda scrubbed.
-"After my front baby teeth and back tooth came out I was obliged to drink juice at dinner since I was unable to chew" Here the adverb clause is: I had juice for dinner.
Understand the concept better?
