If a sentence still makes sense when you can tack the words “by zombies” on the end, it’s in the passive voice and should probably be done away with.
In active voice, the subject of the sentence DOES the action. In passive voice, the subject RECEIVES the action.
- The house was painted last week. (Passive.)
- John painted the house last week. (Active.)
Passive voice is generally a bad thing – not always, it has its uses – but it’s often a sign of weak or lifeless writing. You get constructions like:
- We were given directions to the hospital. Tim was operated on. We were told the operation was successful.
That’s okay, but it’s a bit “flat”. Consider the “active” difference:
- Strangers gave us directions to the hospital. A surgeon operated on Tim. The doctor said the operation was successful.
So where do the zombies come in? It’s a tip from the legendary copy editor Benjamin Dreyer. “If you can append ‘by zombies’ to the end of a sentence, you’ve indeed written a sentence in the passive voice.”
Let’s try it out:
- The house was painted last week by zombies. (Makes sense, therefore it’s passive.)
- John painted the house last week by zombies. (Doesn’t make sense, so it’s not passive.)
Or our mini story:
- We were given directions to the hospital by zombies. Tim was operated on by zombies. We were told the operation was successful by zombies.
But what about when there’s already a “by” at the end of the sentence?
- The window was broken by Barry.
Just replace Barry with zombies. If it still makes sense, it’s passive.