Locate the complete gerund or infinitive phrase and identify its use. jumping rope was the child's favorite game.

In the sentence given, it is a gerund and not an infinitive phrase. The complete gerund phrase in the sentence is "jumping rope". The gerund is the word "jumping". A gerund is a word that takes the - ing form of the verb, but functions as a noun. This gerund phrase is used as the subject of the sentence.