passive voice ? help me pliz

[kutu_suci]

all i know about passive voice is Obj + to be + Verb + Subjct, but how bout these sentence :
- i need my letter stamped by him so i can send it
- i need my piece approved by him before i can publish it
- more children being treated for bipolar disorder
- help needed


my question is, why they don't use "to be" between the Obj and Verb ? yea, i feel it'll be weird if i put "to be" on it but that is the form isnt it ? or maybe those sentence are wrong ? and if those are wrong, would you give me some right sentences for me pliz . . . . thank you so much ^_^

[kutu_suci]

help me pliz

[David L.]

i need my letter stamped by him so i can send it
I need my letter to be stamped by him so that I can send it
This is the correct grammatical form...but do you really want to say all that? In speaking, we tend to omit certain words and 'take for granted' that they are there - we still get the meaning of what is being said.

- i need my piece approved by him before i can publish it
I need my piece to be approved by him before I can publish it.

- more children being treated for bipolar disorder
More Children are being treated for bipolar disorder by their local GP than as inpatients these days.
- help needed
Help is needed by an elderly lady who is confined to a wheelchair. Two mornings a week, light cleaning. Please leave phone number with the vicar.
I should stress that no native speaker would ever come out with these utterances except in classroom 'grammar exercises'!