The passive is used:
- when the action is more important than the person doing it
The World Wide Web was invented by Tim Berners-Lee.
- when we don't know who did something
Paper was invented in China.
- when reporting the news, and in academic and scientific writing where we are more interested in events and processes than in the person doing the action
The conference on Internet marketing is held every year in September.

Formation of the passive
The passive is formed with the verb be and the past participle of a transitive verb.
For modals it is formed with the modal + be + past participle.
simple present It is made
present continuous It is being made
present perfect It has been made
simple past It was made
past continuous It was being made
simple future It will be made

Compare these sentences:
A Martin Cooper made the first public mobile phone call.
B The first public mobile phone call was made by Martin Cooper.
Sentence A is active and follows the pattern of Subject (Martin Cooper), Verb (made) and Object (the first public mobile phone call).
Sentence B is passive and the pattern is Subject (the first public mobile phone call), Verb (was made) and Agent (by Martin Cooper).
Sometimes there are two objects:
My uncle gave me a mobile for my birthday.
It is more common to say I was given a mobile by my uncle rather than A mobile was given to me by my uncle.

The infinitive
Where the situation is in the present and an impersonal sentence is needed, we can use the passive form of the verb plus the infinitive.
The language is said to be dying out.
In the past, we use the passive plus the past infinitive.
Silbo is said to have come from Africa.

These activities practise this Grammar: