Here's why:
* Subordinating conjunctions connect a dependent clause (which cannot stand alone) to an independent clause (which can stand alone).
* "Unless" introduces a condition that, if not met, will negate the main statement.
Example:
* Unless you study hard, you will not pass the exam.
Here:
* "Unless you study hard" is a dependent clause.
* "You will not pass the exam" is an independent clause.
Let me know if you'd like more examples!