Have you heard of the “zombie test” for determining whether a sentence contains passive voice? It goes something like this: if you can add by zombies after the verb and have the sentence make grammatical sense, the verb is passive.
Y’see, there are people who will scream at you that every use of a “to be” verb is passive voice, and every time you use one, you’re a Bad Writer ™.
Take the (admittedly bland) sentence, It is raining. Can you add by zombies and have it make sense?
No, you cannot.
(No, not even you over there. Stop being deliberately dense.)
There are people who will scream at you that had is also passive. They’ll tell you the first sentence in this paragraph is passive… and this one, too.
This sentence is passive by zombies.
Nope. Doesn’t work.
Well, what about was, then? Surely it’s passive voice; a thousand or more high school English teachers and university creative writing professors can’t be wrong about something like that.
(That weird sound you just heard is the bell that rings when I hit my sarcasm quota for the week.)
Passive voice happens when the thing you’re talking about is receiving the action of the verb rather than performing the action itself.
Passive: The brains were eaten by zombies.
NOT passive: Zombies were eating the brains.
And here’s another thing you need to know about verbs: Just because a sentence doesn’t contain a super-duper, over-the-top exciting action verb doesn’t mean it’s passive, or even just a bad sentence. Sometimes it is best to say a character ran rather than to say she scampered or zipped or raced or whatever. (The previous sentence is not passive. You can see that now, right?) There seems to be a sort of general-verb version of “said” bookism, a horrible disease that makes (usually newbie) writers want to replace every instance of said with a super-duper, over-the-top speech word that probably isn’t even appropriate. “Brrrraaaaiiiinnnnssss,” the zombie chortled whilst scampering through the town. Don’t be that kind of writer.