Answer:
- Adverb clause: "since she had a test tomorrow"
- subordinating conjunction: "since"
- words modified: "went to bed early"
Step-by-step explanation:
Adverb sentences have the function of an adverb, and in them we have some subordinate conjunctions to connect the dependent sentence (adverbial sentence) to the independent sentence. In fact, the conjunction connects the adverbial prayer with the word contained in the independent prayer that the adverbial prayer will modify.