Past Perfect

Past Perfect

Formation (+)

 Subject+ Had + past participle

                Uses

•     The Past Perfect expresses the idea that something occurred before another action in the past. It can also show that something happened before a specific time in the past.
• 
  
•          The Past Perfect to show that something started in the past and continued up until another action in the past.

For example

• At first I thought I had done (I’d) the right thing, but I soon realized that I had made (I’d) a big mistake.
• They had studied (they’d) English before they went to London.

Formation (?)

Had + Subject+ Past participle ? 

For example:

•  Had they studied English before they went to London?
•   Had I made a big mistake soon I though?