Past Perfect x Past Perfect Continuous: Conceitos básicos

Hello guys!

First off, let me say that I really, really love this site. It helps me a lot. Thaks for making something so great!

Now, I have a terrible difficulty when the matter is English verbs: the use of Past Perfect and Past Perfect Continuous.

I searched topics about it here in EE but I keep in doubt.

What I'd like to know is: When to use them? What's the difference between them? Could you give me some examples (the more the better)?

Thanks for patience!

P.S.: Como ficariam as seguintes frases:

"Ela tinha quebrado a perna antes disso."

"Ele não tinha feito o que eu havia pedido."

"Queria que eu não tivesse comido tanto antes do almoço."

"A polícia queria saber se eu tinha visto alguma coisa".

"O carro dele foi roubado."

(Descupem se me excedi... )

[Thnx]