Answer:
Since we live far away from each other, I received a letter from my friend Ashley. Here, the subordinate conjunction here is "SINCE."
Step-by-step explanation:
A subordinate conjunctions are used to introduce dependent clauses and demonstrate the connection between the main clause and the subordinate clause in a complex sentence.
From the example above, the main clause is "I received a letter from my friend Ashely, " and the subordinate clause is "We live far away from each other."
The main clause is a complete notion that may be expressed in a single sentence. It contains the main subject ("I") and the main verb ("received").
The subordinate clause is unable to form a complete thought on its own because it depends on the main phrase. "We live far away from each other" , and it starts with that subordinating conjunction to tell us more about the conditions around the main sentence.