Question

Identify the italicized part of the sentence.

Answer 1

Even though you didn't italicize anything in this sentence, I managed to find the exercise on the Internet - the italicized part is won.
The correct answer is simple predicate. A simple predicate is usually just one word - a predicate, a verb without objects and adverbs around it. If the part won two first-place ribbons was italicized, then it would be a complete predicate. Stephen is simple subject in this sentence, and at the same time complete subject as well. There are no predicate adjectives in the sentence above.