NB: In the examples below, verbs are emboldened, subjects are highlighted in purple, and objects are highlighted in pink. Additionally, prepositions are occasionally italicised.
Different voices are used to put emphasis either on the subject or the object of a sentence and to express how the object is being affected.
Our focus is primarily on the subject and what they are doing. The verb is in the active voice.
She will pick up the ball. A friend of mine sings a song. They played the game.
NB: In the above example, verbs are emboldened, subjects are highlighted in purple, and objects are highlighted in pink.
Our focus remains primarily on the object and how it is being affected by the subject. The verb is in the passive voice.
The door will be shut by the boy. The last cookie was eaten by Susan. My brother is being beaten up by his partner. The letter was sent from the master of the house.
You will notice that prepositions such as 'by' or 'from' are usually used in the passive voice, as italicised in the above examples.
Active Voice Without Object
This voice puts the entire focus on the subject, eliminating an object altogether, though an object is usually clearly implied. The verb is in the active voice without an object.
I sang. They said. Her father jumped.
Passive Voice Without Object
This voice puts the entire focus onto the object and how it is affected by the subject, without mentioning the subject directly. A subject is usually implied, however. The verb is in the active voice without an object.
The door is being shut. The lights were dimmed. A voice was heard.