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The passive is formed with the verb to be (is/was/have been etc.) and the past participle (done/cleaned/seen etc.):

			The sculpture is made of glass and plastic.
			That toy was made in China.
			All staff have been informed of the changes.

The following forms are common:

http://www.edufind.com/english/grammar/Pass1.cfm

When we say what a person or thing does, we use an active verb:

			My brother built his own house.
			We all speak Spanish.
			The man is repairing the fridge at the moment.

When we say what happens to a person or thing – what is done to them – we use a passive verb:

			All of those houses were built by my brother.
			Spanish is spoken in most Latin American countries.
			I came by bus because my car is being repaired.

Some verbs cannot have passive forms. Intransitive verbs , such as sleep, die, fall, or arrive, which do not take an object, do not have a passive form.

Also, stative verbs are not usually used in the passive.

			We all have university degrees (NOT University degrees are had by us all)
			I see what you mean (NOT What you mean is seen by me)

Many learners confuse active and passive verb forms because, as Swan points out in Practical English Usage (OUP; 1997) :

"Be is used to make both passive verb forms and active progressive tenses."

p. 409

			Your orders are being processed right now.
			We are processing your orders right now.

And "past participles are used to make both passive verb forms and active perfect tenses."

p. 409

			The toy was made in China.
			He has made a terrible mistake.

For more information about passive verb forms, see the following web sites:

http://andromeda.rutgers.edu/~jlynch/Writing/p.html