Final answer:
The given sentence, 'The moon was bright,' is a simple sentence. A simple sentence has just one independent clause, which means it expresses a complete thought and can stand alone as a sentence.
Step-by-step explanation:
The given sentence, 'The moon was bright,' is a simple sentence. A simple sentence has just one independent clause, which means it expresses a complete thought and can stand alone as a sentence. In this case, the subject of the sentence is 'the moon,' and the verb is 'was bright.' The sentence does not contain any dependent clauses or conjunctions to make it compound or complex.