Final answer:
To change the active sentence 'My friend sent a letter to her mother' into passive voice, it becomes 'A letter was sent to her mother by my friend.' The passive voice focuses on the action rather than the doer.
Step-by-step explanation:
To change the statement 'My friend sent a letter to her mother' into the passive voice, we need to make the object ('a letter') the subject of the sentence. The transformed sentence in the passive voice will read: 'A letter was sent to her mother by my friend'. This change emphasizes the action (the letter being sent) rather than who performed the action (my friend).
In the passive voice construction, the focus often shifts to the action or the object being acted upon, rather than the doer of the action, especially when the doer's identity is not as important, or if the writer wants to omit the specifics about the doer. Writers might use the passive voice for various reasons, such as to maintain formal tone or to focus on the recipient of the action instead of the initiator.
It's also worth noting that while passive voice can be a useful tool in writing, overuse can lead to a lack of clarity or directness, so it should be employed judiciously. Active voice tends to be more direct and vigorous, which is often preferred for strong, clear writing. However, there are instances when passive voice is the better choice, depending on the context and the writer's purpose.