Let's break down why:
* Infinitive Phrases: An infinitive phrase is a group of words that includes the infinitive form of a verb (to + verb) and its modifiers. For example, "to eat quickly" or "to run a marathon."
* The Sentence: "Johnna went to the store shop" is a simple sentence with a subject (Johnna) and a verb (went). There's no infinitive form of a verb ("to + verb") present.
Possible Error: It's possible the sentence is meant to be something like "Johnna went to the store to shop," which would include the infinitive phrase "to shop."