分唔清英文tenses

我以前在 Yahoo 回答過你提及的 tenses, (除了 Past perfect 之外), space有限, 不能這裡重述, 請瀏覽以下:

Present perfect and past simple tense:
http://hk.knowledge.yahoo.com/question/question?qid=7012010100632

Present perfect continuous and Past perfect continuous
http://hk.knowledge.yahoo.com/question/question?qid=7011120300464

PAST PERFECT:

Form: Had + past participle

We use past perfect for an action or a state which is completed before a time in the past. We can include a specific time reference.

By the time we arrived at the railway station, the train had left.

兩件事發生在以前 (past) , 一先一後, 與現在無關.焦點在一件事已經完成.
火車離開先, 後我們抵達火車站
用past perfect 著重火車已經離開, (completed the action), time reference 是我們抵達火車站.

Another example:
When we got back we found that the babysitter had already gone home.

Past simple and past perfect
When the boss arrived, the meeting began.
(The boss arrived and then the meeting began.)

When the boss arrived, the meeting had begun.
(The meeting began before the boss arrived.)

We use past simple when one action comes immediately after the other.

Well, 如果有什麼不明白, email我.

2012-02-15 04:09:14 補充：
gone 在這裡不是 past participle, 不是用在 passive voice.
Gone是作形容詞.字典有

gone (adjective) = to be dead or no longer exist.

He is gone = he is dead

Tense means time in grammar. The tense of a verb tells you when the action of the verb takes place. There are Present perfect continuous tense,,and Present perfect tense.
Present perfect continuous tense:-eg I've been studying maths. since morning.
Present perfect tense:-Form: have + pp
Usage:-(1)just completed action and means started in the past and just recently finished or still going on:with the words:- already, just, now, yet, not yet, by this time,
eg:-She has learned English already.
(2)from past to present experience:- with the words:- ever, never, before, once, twice, after, seldom,
eg:-Have you ever seen a tank?
I have not seen him once.