Here's why:
* Clauses are groups of words containing a subject and a verb.
* Independent clauses can stand alone as complete sentences.
* Dependent clauses cannot stand alone and rely on an independent clause for meaning.
Possible scenarios:
* If the sentence were "Before Samantha can take her driving test, she needs to practice more", it would have two clauses:
* Independent Clause: "She needs to practice more."
* Dependent Clause: "Before Samantha can take her driving test"
* If the sentence were "Before Samantha can take her driving test?", it would have one clause (a dependent clause) that needs an independent clause to make it a complete sentence.