Answer:
Your answer would be "walked to the park".
Explanation:
The complete predicate of the sentence above is "walked to the park". The predicate tells us what the subject does or is. In this way, it can be said that it modifies the subject. You can also say that the predicate is everything that is not the subject, so if you identify the subject, then you'll be able to identify the predicate. Ask the following question: Who verb/ed? That is, who walked to the park? The answer to that question is "we", the subject of the sentence. Then, the VP "walked to the park" is the complete predicate.