1. The playful puppy chased its tail.
* Complete Subject: The playful puppy
* Simple Subject: puppy
2. My best friend and I are going to the movies tonight.
* Complete Subject: My best friend and I
* Simple Subject: friend and I
3. The giant, red oak tree stands tall in the park.
* Complete Subject: The giant, red oak tree
* Simple Subject: tree
Remember:
* The complete subject includes the simple subject (the noun or pronoun that the sentence is about) and any words that modify it.
* The simple subject is the main noun or pronoun.