文法問題............................................

我想再講得詳細少少:

had been 同 has been 都係 perfect tense, 用黎講一d完成左既事
depends on 相對於幾時 果件事係完成左呢?

如果係相對於現在係完成左就用 present perfect (has been)
如果o係過去某一刻都已經係完成左既就用 past perfect (had been)

如果唔係好clear,再睇睇:
present perfect (has been)既用法:
1 剛剛完成左d野:
I have finished my homework.
She has just eaten.
2 講到現在為止,做過一樣野幾多次:
I have been to Japan for 3 times
2 講由過去某一刻到現在, 好耐冇做一樣野:
I have not cleaned my room since last week
I have not been to China since 2005.
有冇發現所有例子都同現在係有關呢?

如果係past perfect (had been), 就只可以用黎講過去某一刻已完成某事:
用番I have finished my homework果句:
I had finished my homework before I took my shower yesterday.
有時如果你作文,成篇都係關於過去既, 例如講你細個既時候, 咁past perfect 就好有用喇,否則, has been就比較常用

就係咁...

Had been是屬於過去完成式, has been 是屬於現在完成式.

Had been是指某事在過去某段時間已經完成. Has been是用來形容直至目前為止(即現今)某些事已成完成. 兩者屬於完成式, 皆沒清楚註明事情是何年/何月/何日發生, 只能說明自從某段時間後事情發展模樣. 例如:

He has not gone to United States since the occurence of 911 incident.
自從911事件後, 他已沒有往美國了.

Has been即係一件過去的事,但句中沒有說明時間
如果1句sentence內有2件己過去的事,早D發生用past perfect(had been),後用simple past