A phrase in which the key word is an adverb is called an adverb phrase.
A subordinate clause that performs the function of an adverb in a sentence is called an adverb clause.
|I turned off all lights before leaving.
||I turned off all lights before I left.
I turned off all lights before leaving.(adverb phrase)
In the above sentence “before leaving” is an adverb phrase.
I turned off all lights before I left. (adverb clause)
In the above sentence “before I left' is an adverb clause as it contains a subject (I) and a predicate (left).
1. Because she has a college degree, she was given a good promotion.
2.When the storm started, he was at the market.
3.We served drinks when our friends arrived.