Final answer:
In the sentence given, 'Dallas' is both the simple subject and the complete subject as it is the main word that tells who is experiencing the three-digit temperatures.
Step-by-step explanation:
To find the complete subject and the simple subject in the sentence 'Dallas has had three-digit temperatures for over thirty days,' you first need to understand what each term means. The complete subject includes all of the words that tell who or what the sentence is about, while the simple subject is the main word in the complete subject, which is typically a noun or pronoun.
In this sentence, the complete subject is 'Dallas' because it includes all the words that tell us who has had three-digit temperatures. 'Dallas' is also the simple subject because it is the main word in the subject portion of the sentence that tells us who is experiencing the three-digit temperatures.