怎樣應用past perfect continuous tense

Past perfect continuous tense 主要用於過去「某段時間」內持續發生嘅事情但現在或之前已經結束
The fight had been lasting for one hour.
打鬥持續了一小時
I had been working for my former employer for two years.
我為我的前僱主工作了兩年
I had been studying in my primary school for six years.
我在我的小學學習了六年