Sometimes a sentence is turned around to shift the focus of the sentence. The thing that receives the action (which would normally be the Direct object) is stated as the subject. The verb is changed into a passive form. And the cause of the action (which would normally be the subject) is either unstated, or expressed in some kind of prepositional phrase. The purpose of a passive sentence is either to emphasize that which receives the action or to leave the cause of the action unstated.
Passive Verbs: Verb that emphasizes the receiver of the action by making it the subject. The passive verbs are highlighted in the following sentences.
The passive sentences are contrasted with a typical construction.
Typical Passive
Jim broke the window. The window was broken
Typical Passive
Jim threw the ball The ball was thrown by Jim
Click on the Passive Verbs in the following sentences.