Sometimes the most important part of a sentence is not the person who does the action. It is the thing that the action happens to. Imagine you come to work and see a broken window. You do not know who broke it, and maybe you do not care. You just want to say: 'The window was broken last night.' That is the passive voice, and English speakers use it all the time.

Without the passive, you get stuck when the doer is unknown, obvious, or not important. You hear it in news ('Two people were injured'), at work ('The email was sent this morning'), and in shops ('These bags are made in Italy'). If you can understand and build the passive, you can talk about results and events without always saying who did them.

First, remember how an active sentence works. In 'Maria cleaned the office', Maria is the subject and the doer. The office receives the action; it is the object. Active sentences put the doer first. Most of your English so far has been active, and that is fine — active is still the normal choice.

The passive turns the sentence around. The thing that receives the action moves to the front and becomes the subject: 'The office was cleaned.' To build it, you need two pieces: a form of the verb 'be' (is, are, was, were) plus the past participle of the main verb. The past participle is the third form: clean → cleaned, make → made, break → broken, write → written. So the recipe is simple: subject + be + past participle.

What happens to the doer? Most of the time, you just drop it. 'The office was cleaned' is complete. If the doer really matters, you can add it at the end with 'by': 'The office was cleaned by a new company.' But only add 'by' when that information is useful. If everyone knows or nobody cares who did it, leave it out.

When should you choose passive instead of active? Use it when the doer is unknown ('My bike was stolen'), when the doer is obvious ('He was arrested' — clearly by the police), or when the result is simply more important than the person ('Dinner is served'). If the doer is the interesting part of your message, stay active: 'My grandmother made this cake' sounds much better than 'This cake was made by my grandmother' in everyday talk.

One more key point: only verbs that take an object can go passive. You can say 'The letter was written' because you can write something. But verbs like 'arrive', 'happen', or 'sleep' have no object, so they have no passive. 'The accident was happened' is impossible — say 'The accident happened.'

1. 1. My wallet was stolen on the train.

   The thief is unknown, so the passive works perfectly and no 'by' phrase is needed.

2. 2. These shoes are made in Vietnam.

   Present passive 'are made' describes a general fact about a product.

3. 3. The meeting was cancelled this morning.

   The result matters, not the person who cancelled it.

4. 4. Rice is grown in the south of the country.

   Present passive for something that happens generally; the farmers are obvious.

5. 5. Was your car damaged in the storm?

   In a passive question, 'be' moves before the subject: Was + your car + damaged.

6. 6. The rooms are cleaned every morning at eight.

   Plural subject takes 'are'; the hotel staff are obvious, so they are dropped.

7. 7. This photo was taken by my sister.

   The 'by' phrase appears because the doer is interesting information.

8. 8. The tickets weren't checked at the gate.

   Negative passive: just add 'not' after 'be' (were not / weren't).

9. 9. English is spoken in many countries.

   A classic fact-style passive; naming every speaker would be impossible.

10. 10. The old bridge was built in 1902.

    Past passive for history; the builders are unknown and unimportant.

11. 11. Lunch is served between twelve and two.

    Restaurants use the passive to focus on the service, not the waiters.

12. 12. Two workers were injured at the factory.

    News style: the injured people are the story, not the cause.

13. 13. Is breakfast included in the price?

    A useful travel question built with is + past participle.

14. 14. The results are checked twice before we send them.

    Passive and active can sit together; the checker is unimportant, the sender is 'we'.

The biggest mistake is dropping the verb 'be'. Learners say 'The report finished yesterday by me' instead of 'The report was finished yesterday.' Without 'was', the sentence is not passive at all — it reads as if the report did something by itself. The passive always needs two parts: be + past participle. If one part is missing, the pattern breaks.

A second mistake is adding a 'by' phrase that nobody needs, especially 'by me' or 'by people'. 'The report was finished by me' is grammatical but strange; if you want to talk about yourself, use active: 'I finished the report.' Save 'by' for doers that add real information: 'The song was written by a teenager.'

Third, learners try to make passives from verbs with no object. Wrong: 'The problem was happened last week.' Right: 'The problem happened last week.' Verbs like happen, arrive, die, and sleep never take the passive, because nothing receives their action.

• Passive recipe: subject + be + past participle. Both parts, always.
• If the doer is unknown, obvious, or boring, drop it.
• Only add 'by...' when the doer is real news.
• If you want to talk about yourself, stay active: 'I did it.'
• No object in the active sentence? Then no passive exists.
• Match 'be' to the subject: it was cleaned, they were cleaned.