วันพฤหัสบดีที่ 12 มกราคม พ.ศ. 2555

PAST PERFECT


Past Perfect
FORM
[had + past participle]
Examples:
    You had studied English before you moved to New York.
    Had you studied English before you moved to New York?
    You had not studied English before you moved to New York.
Complete List of Past Perfect Forms
USE 1 Completed Action Before Something in the Past
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.
Examples:
    I had never seen such a beautiful beach before I went to Kauai.
    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.
USE 2 Duration Before Something in the Past (Non-Continuous Verbs)
With Non-Continuous Verbs and some non-continuous uses of Mixed Verbs, we use the Past Perfect to show that something started in the past and continued up until another action in the past.
Examples:
    We had had that car for ten years before it broke down.
    By the time Alex finished his studies, he had been in London for over eight years.
    They felt bad about selling the house because they had owned it for more than forty years.
Although the above use of Past Perfect is normally limited to Non-Continuous Verbs and non-continuous uses of Mixed Verbs, the words "live," "work," "teach," and "study" are sometimes used in this way even though they are NOT Non-Continuous Verbs.
IMPORTANT Specific Times with the Past Perfect 
Unlike with the Present Perfect, it is possible to use specific time words or phrases with the Past Perfect. Although this is possible, it is usually not necessary.
Example:
    She had visited her Japanese relatives once in 1993 before she moved in with them in 1996.
MOREOVER
If the Past Perfect action did occur at a specific time, the Simple Past can be used instead of the Past Perfect when "before" or "after" is used in the sentence. The words "before" and "after" actually tell you what happens first, so the Past Perfect is optional. For this reason, both sentences below are correct.
Examples:
    She had visited her Japanese relatives once in 1993 before she moved in with them in 1996.
    She visited her Japanese relatives once in 1993 before she moved in with them in 1996.
HOWEVER
If the Past Perfect is not referring to an action at a specific time, Past Perfect is not optional. Compare the examples below. Here Past Perfect is referring to a lack of experience rather than an action at a specific time. For this reason, Simple Past cannot be used.
Examples:
    She never saw a bear before she moved to Alaska. Not Correct
    She had never seen a bear before she moved to Alaska. Correct
ADVERB PLACEMENT
The examples below show the placement for grammar adverbs such as: always, only, never, ever, still, just, etc.
Examples:
    You had previously studied English before you moved to New York.
    Had you previously studied English before you moved to New York?
ACTIVE / PASSIVE
Examples:
    George had repaired many cars before he received his mechanic's license. Active
    Many cars had been repaired by George before he received his mechanic's license. Passive


Past Perfect Forms
Positive
Negative
Question
had finished.
You had finished.
We had finished.
They had finished.
He had finished.
She had finished.
It had finished.
had not finished.
You had not finished.
We had not finished.
They had not finished.
He had not finished.
She had not finished.
It had not finished.
Had I finished?
Had you finished?
Had we finished?
Had they finished?
Had he finished?
Had she finished?
Had it finished?