Is this sentence a simple sentence, compound sentence, complex sentence, or compound-complex sentence? Before she drove across the state, Ashley made sure her gas tank was full.

This is a complex sentence.

Explanation:

A complex sentence is formed by joining an independent clause and a dependent one. An independent clause is a group of words that can stand alone as a sentence, expressing a complete thought. On the other hand, a dependent or subordinate clause does not make sense on its own. Dependent clauses begin with subordinating conjunctions, such as "because", "before", "though", "after", etc.

Let's divide the sentence given:

1. Ashley made sure her gas tank was full. --> independent clause

2. Before she drove across the state --> dependent clause

Therefore, what we have here is a complex sentence.

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