Past Perfect

Past Perfect Tense
The past perfect tense is used to show that one action in a sentence finishes before a second action begins. Words like before and after are indicators that the past perfecttense may be used; however, there are no strict rules for this situation. You must choose the best verb tense for your sentence.
The past perfect is created by using I had, you had, he/she had, we had,you had or they had + past participle.
The structure of the past perfect tense is:
subject | + | auxiliary verb HAVE | + | main verb |
| conjugated in simple past tense | | past participle || had | | V3 |
For negative sentences in the past perfect tense, we insert not between the auxiliary verb and main verb. For question sentences, we exchange the subject and auxiliary verb. Lookat these example sentences with the past perfect tense:
  | subject | auxiliary verb | | main verb |   |
+ | I | had |   | finished | my work. |
+ | You | had |   | stopped | before me. |
- |She | had | not | gone | to school. |
- | We | had | not | left. |   |
? | Had | you |   | arrived? |   |
? | Had | they |   | eaten | dinner? |
When speaking with the past perfect tense, weoften contract the subject and auxiliary verb:
I had | I'd |
you had | you'd |
he had
she had
it had | he'd
she'd
it'd |
we had | we'd |
they had | they'd |
 
The 'd contraction isalso used for the auxiliary verb would. For example, we'd can mean:
* We had
or
* We would
But usually the main verb is in a different form, for example:
* We had arrived (pastparticiple)
* We would arrive (base)
It is always clear from the context.

After
After he tied his shoes, he left the house.
After he had tied his shoes, he left the house.
She watched a videoafter the children had gone to bed.
 I arrived at the cinema after the film had started.

Before
Before I went to the park, I had finished my work.
Before he sang a song he had played the guitar....