Grammar: Passive

Passive is used if we are interested in the object or we don't know who caused the action.

Example: Homework is required in class

We can only form a passive sentence from an active sentence when there is an object in the active.

How to do it from an active sentence?

• Use verb to be + past participle of the verb
• Object of the "active" sentence becomes subject in the "passive" sentence
• Subject of the "active" sentence becomes "object" in the "passive" sentence" (or is left out)

Example: (active) They build a house -> (passive) The house is built by them

More Examples:

Tense	Active	Passive
present simple	I make a cake.	A cake is made (by me).
present continuous	I am making a cake.	A cake is being made (by me).
past simple	I made a cake.	A cake was made (by me).
past continuous	I was making a cake.	A cake was being made (by me).
present perfect	I have made a cake.	A cake has been made (by me).
pres. perf. continuous	I have been making a cake.	A cake has been being made (by me).
past perfect	I had made a cake.	A cake had been made (by me).
future simple	I will make a cake.	A cake will be made (by me).
future perfect	I will have made a cake.	A cake will have been made (by me).

Exercise:

1. Identify the active or passive voice
2. Identify the active or passive voice
3. Rewrite in passive 
4. Rewrite in passive
5. Write the verb in the right passive form using simple past
6. Write the verb in the right passive form using simple present
7. Difficult Exercise (mixed)

Modified from English Hilfen and Perfect English Grammar