Answer:
Fred swam in the deep end of the pool.
Step-by-step explanation:
In an active voice, the action of the verb is done/ performed by the subject of the sentence. Whereas in a passive voice, the action of the verb acted upon the subject of the sentence. Meaning, in an active voice, the subject comes before the action/ verb whereas in a passive voice, the subject comes after the verb/ action.
In the given sentences, the subject is Fred while the action/ verb is the act of swimming in the pool. So, in an active voice, Fred will do the action while in the passive voice, the action/ verb will be acted upon by Fred.
Thus, "The deep end of the pool was swum in by Fred" is in the passive voice while "Fred swam in the deep end of the pool" is in the active voice.