Past Perfect

Two events that happened in the past, one before the other.

Same problem as Present Perfect. Not commonly used in some languages.

Makes it difficult to learn to use in English. However, this is "a must learn" grammar.

had + past participle verb, past tense verb

EXAMPLES:

John was at the airport for an hour. The airline cancelled his flight.

John had been at the airport for an hour when the airline cancelled his flight.
I was in Rio just one day. I got robbed.

I had been in Rio just one day when I got robbed. CLS
I worked in Paris for a year. I moved to California.

I had worked in Paris for a year, before I moved to California.
You met your wife in Bogota. How long were you there.

When you met your future wife Bogota, how long had you been there?

NOTE: Other tenses

PAST TENSE: I conducted interviews all day yesterday.
PRESENT TENSE: I conduct interviews every day.
FUTURE TENSE: I will conduct interviews all day tomorrow.
PRESENT PERFECT: I have conducted interviews since Monday.
PAST PERFECT: I had conducted interviews all day when I began to feel bad.