English Passive

          There are some aspects of English grammar that can be presented as a kind of formula. Active and Passive sentences are an example of this. The most common type of sentence in English is an Active sentence, which has an Actor + Verb + Receiver, such as John robbed the bank, or an Actor + Verb, such as John slept, which has no Receiver. We can change an Active sentence into a Passive one by changing the positions of the Actor and Receiver, moving the Actor to the end of the sentence and moving the Receiver to the beginning of the sentence: Actor + Verb + Receiver ==> Receiver + Be + Past Participle + by + Actor. For example, John robbed the bank. ==> The bank was robbed by John.  Passive sentences always have some form of Be: be, for future tense and modals, am, is, are for Simple Present Tense, was, were for Simple Past Tense, being for Present Progressive, and been for Present Perfect. That's how to form a Passive sentence, but when do we use Passive sentences instead of Active ones?

We use Passive sentences in these four situations:

1. No one knows who the Actor is.  The bank was robbed (by someone).
2. We don't want to say who the Actor is.  The window was broken (by someone).  I know who broke the window (the Actor), but I'm not going to say.
3. Everyone knows who the Actor is. Rice is grown in China.  Everyone knows that Chinese people grow rice in China.
4. We want to put the emphasis, or focus, on the Receiver. In the Passive sentence, The man was bitten by the dog,  I'm more concerned about the man than the dog.

I want to leave you with a question. Can you make a Passive sentence out of an Active sentence that has no Receiver, like John died? If not, why not?