the past perfect simple

We use the past perfect
simple to talk about what happened before a point in the past. It looks
back from a point in the past to further in the past.

• 
  I hadn't known the bad news when I spoke to him.
  
• 
  I checked with the supplier and they still hadn't received the contract.
  
• 
  She had already told him before I got a chance to give him my version.
  
• 
  The company has started the year well but was badly hit by the postal strike.
  

The past perfect simple is often used when we report what people had said/thought/believed.

• 
  He told me they had already paid the bill.
  
• 
  He said he believed that John had moved to Italy.
  
• 
  I thought we had already decided on a name for this product.
  

We use the past perfect continuous to look back at a situation in progress.

• 
  It looked like a good time to invest. Inflation had been falling for several months.
  
• 
  Before I changed jobs, I had been working on a plan to reduce production costs.
  
• 
  We had been thinking about doing that but then decided against it.