Past Perfect - Quá khứ Hoàn thành

FORM of Past Perfect

The Past Perfect has two parts: the past tense of the verb 'to have' (=had) + the past participle (PP) of the main verb. See examples below.

S + had + PP	I had learnt English. He had swum well. They had watched TV.
S + had not+ PP	I hadn't learnt English. He hadn't swum well. They had not watched TV.
Had + S + PP?	Had you learnt English? Had he swum well? Had they watched TV?

The Past Perfect refers to an event earlier than a specific event in the past. It is used to make it clear that one event happened before another in the past. It does not matter which event is mentioned first - the tense makes it clear which one happened first.

In the following example, Event A happens before Event B.

USEs of Past Perfect

1. to describe a completed action before an event in the past.

• I did not have any money because I had lost my wallet.
• Tony knew Istanbul so well because he had visited the city several times.
• Had Susan ever studied Thai before she moved to Thailand?
• She only understood the movie because she had read the book.
• Kristine had never been to an opera before last night.
• We were not able to get a hotel room because we had not booked in advance.
• A: Had you ever visited the U.S. before your trip in 2006?
  B: Yes, I had been to the U.S. once before.

2. Past Perfect + just

'Just' is used with the past perfect to refer to an event that was only a short time earlier than the later event.

• She had just left when he arrived.
• They had just turned on the TV when the electricity is out.

Forms of Negatives and Questions

Negative sentences and questions are formed with the auxiliary verb 'had'.

• She hadn't got an English certificate when she got the job.
• Had it rained before you came to London?