The Past Perfect Simple Tense
The perfect simple is used to describe an event before another event in the past.
For example, say yesterday you played soccer, then you went swimming, you would say:
Yesterday I had played soccer, had went swimming, had ran 10 miles, then played tennis. As we see, the events happened in the past.
(1st event) (2nd event) (3rd event) then the last event( played tennis)
We also have the past perfect continuous. This is used to describe an event (or activity) to describe a continuing (連続) before another event happened, for example:
I was reading a book when the door rang
So, what is the difference in past perfect and past perfect continuous?
Look at this past perfect sentence:
I ran to work then I ate a sandwich
Then this past perfect continuous
I was running to work while I ate a sandwich
The past perfect is for events happening 順番 1,2,3
The past perfect continuous is for explaining you were doing something when something else happened. (何かする間何かした）
I, she, he, it: was reading.
You, we, they: were reading.
I, she, he, it: studied
You, we, they: studied
Past perfect continuous:
I, she, he, it: had been walking.
You, we, they: had been walking.
The past perfect continuous is used to describe an action in a period of time before something else happened, whereas past continuous is more a focus on something you used to do often. This is a simple explanation, and it will be enough here.