Grammar Girl here.

Today's topic is active voice versus passive voice.

Here's Brian from Iowa:

“It drives me crazy when people write in passive voice. How can I teach people how to tell the difference between passive and active voice and stay away from passive voice? Thanks.”

A lot of you have asked me to explain passive voice and how to avoid it.

I'll start with active voice because it's simpler. In an active sentence, the subject is doing the action. A very straightforward example is the sentence "Steve loves Amy." Steve is the subject, and he is doing the action: he loves Amy, the object. Another example is the title of the Marvin Gaye song I Heard It through the Grapevine. I is the subject, the one who is doing the action. I is hearing it, the object of the sentence.

In passive voice the target of the action gets promoted to the subject position. Instead of saying, "Steve loves Amy," I would say, "Amy is loved by Steve." The subject of the sentence becomes Amy, but she isn't doing anything. Rather, she is just the recipient of Steve's love. The focus of the sentence has changed from Steve to Amy. If you wanted to make the title of the Marvin Gaye song passive, you would say It Was Heard by Me through the Grapevine, not such a catchy title anymore.

A lot of people think that all sentences that contain a form of the verb to be are in passive voice, but that isn't true. For example, the sentence "I am holding a pen" is in active voice, but it uses the verb am, which is a form of to be. The passive form of that sentence is "The pen is being held by me."

Another important point is that passive sentences aren't incorrect; it’s just that they often aren't the best way to phrase your thoughts. Sometimes passive voice is awkward and other times it’s vague.

When you put sentences in passive voice, it's easy to leave out the agent doing the action. For example, "Amy is loved" is passive. The problem with that sentence is that you don't know who loves Amy. In fact, politicians often use passive voice to intentionally obscure the idea of who is taking the action. Ronald Reagan famously said, “Mistakes were made” when referring to the Iran-Contra scandal. Other examples of passive voice for political reasons could include “Bombs were dropped” and “Shots were fired.” Since I started writing this episode, I've become more aware of passive voice, and it seems as if I hear politicians use it every day.

So, these are some of the reasons to avoid passive voice: the form can lead to awkward sentences and obscured meaning. Also, passive voice is wordy. You can tighten up your writing a lot if you use active voice more often than passive.

On the other hand, Mike from Chicago correctly pointed out that there are instances where passive voice is the best choice. If you don't know who is taking the action, then you can't name that person. Depending on the context, it might make more sense to write, “The cookies were stolen,” instead of, “Somebody stole the cookies.” It's a subtle difference. If you want to put the focus on the cookies, use passive voice. Alternatively, if you want to put the focus on the unknown thief, use active voice. If you were writing a mystery novel you might want to highlight the cookies if their specific disappearance were central to the story. So you would choose passive voice and say, “The cookies were stolen.” So passive voice is often a good choice when the actor isn't known or doesn't matter, or if you want to create some mystery around your sentence.

So remember, in a passive-voice sentence the subject of the sentence is the receiver of the action. Passive voice is not grammatically incorrect; it's just not often the best choice. If you know who did what, it’s better to use an active sentence in most cases.

That's all.

I apologize for posting the show late this week,but I have a really good excuse. I was putting the final touches on my new audiobook: Grammar Girl's Quick and Dirty Tips to Clean Up Your Writing. I'm so excited to have it out. It's a one-hour downloadable audiobook covering 24 different topics. The content is mostly from the podcast archives, but there is some new stuff mixed in, the shows are grouped by topic, it's higher quality audio than you get from the podcasts, and it's just grammar (so there aren't any listener questions or announcements like you get in the podcasts).

You can buy the book right now at audible.com, and it will be available in a day or two in the audiobooks section at iTunes. If you've ever wanted to support the show, this is a great way to do it. I think it's a great deal too: It's only $4.95 and you get something really useful. Also, I want the people at my publishing company to be happy that they took a chance on a podcaster. So please, buy the book.

As always, this is Grammar Girl. You'll find a transcript of this podcast at QuickAndDirtyTips.com Remember, if you want to call in with a question, the number is 206-338-GIRL. Send e-mails to feedback@quickanddirtytips.com.

Web Bonus: Advanced Material

One way to tell your sentence is passive is if the subject isn't taking a direct action. In addition, a passive-voice sentence will always contain a past participle, it will usually contain a form of the verb to be, and it will sometimes contain the word by. These three sentences contain one or more passive-voice components: Shot in the leg, he hobbled to the hospital. He was shot in the leg. The purse-snatcher was shot in the leg by the angry grandma.

Thank you to Steve Thornton and Bonnie Trenga