The dog was bitten by the man.
This is passive. Research has shown that many readers miss the intending meaning and instead think that the dog bit the man. However, for whatever reason the biting occurred (hunger or revenge come to mind), the dog was an innocent bystander in this particular sentence. Here’s the active version:
The man bit the dog.
Key phrases such as ‘was being’ or ‘had’ are good indicators. Look for them in your writing and see if an active version can be used instead. You’ll most likely use passive by accident. It tends to creep into our everyday speech, and can make things sounds a bit more formal. If you’re unsure, just think about who is being ‘bitten’ in the sentence, if you were to change the verb.
But there’s no need to entirely boycott the passive tense. It has its uses. It can be understood by humans!
The most salient reason for using passive tense is to centre the sentence on the important character. Instead of focusing on the hungry man, we focus on the dog. This is particularly important if the dog is the main protagonist, or if we are currently following the dog’s actions, rather than the man’s.
For someone who has never considered whether they use passive or active tense, it’s a powerful tool. Learn it, learn how to manipulate it, and never again let it use you.