Which of the following are examples of active voice in writing?

Active voice in writing emphasizes the subject of the sentence as the doer of the action, creating clarity and directness in communication. In the example provided, "Joe logs purchases and verifies account numbers," the subject (Joe) is performing the actions of logging purchases and verifying account numbers. This structure directly connects the subject to the action, illustrating a clear and engaging style of writing.

In contrast, the other examples utilize a passive voice construction, where the subject is acted upon rather than performing the action. For instance, in "Complaints are investigated by our department," the focus is on the complaints rather than on the department that is doing the investigating. Similarly, "A complaint has been received about the billing" emphasizes the receipt of the complaint instead of who received it, thus relegating the doer to a less prominent position in the sentence.

Therefore, the first example distinctly exemplifies active voice, demonstrating a strong, clear connection between subject and action that enhances the readability and impact of the writing.