what is diffrence between future perfect tense and perfect past tense
Past Perfect Tense describes an action completed before a certain moment in the past.
Instance of the same is:
I met him in New York in 2006. I had seen him last five years before.
If two actions happened in the past, it may be necessary to show which action happened earlier than the other. The Past Perfect is mainly used in such situations. The simple past is used in one clause and the Past Perfect in the other; as,
When I reached the station, the train had started running.
I had written the letter before he arrived.
Future Perfect Tense, on the other hand, is used to talk about actions that will be completed by a certain future time.
Future Perfect Tense:
By the end of this month, I will have studied in this school for 7 years.
Her brother will have left before you go to see him.