The past perfect tense is used to describe actions that were completed before a specific time in the past, while the past perfect continuous tense is used to describe actions that began in the past, were in progress up to a specific time in the past, and may or may not have continued beyond that point.

Here are some examples that illustrate the difference between the past perfect and past perfect continuous tenses:

1. Past perfect: “I had eaten breakfast before you called me at 8 o’clock this morning.” (action that was completed before a specific time in the past)
   
   Past perfect continuous: “I had been eating breakfast for an hour when you called me at 8 o’clock this morning.” (action that began in the past, was in progress up to a specific time in the past, and may or may not have continued beyond that point)
   
2. Past perfect: “The sun had risen in the east before I looked outside at 6 o’clock this morning.” (action that was completed before a specific time in the past)
   
   Past perfect continuous: “The sun had been rising in the east for an hour when I looked outside at 6 o’clock this morning.” (action that began in the past, was in progress up to a specific time in the past, and may or may not have continued beyond that point)
   
3. Past perfect: “She had spoken Spanish fluently before I arrived at 7 o’clock this morning.” (action that was completed before a specific time in the past)
   
   Past perfect continuous: “She had been speaking Spanish on the phone with her friend for an hour when I arrived at 7 o’clock this morning.” (action that began in the past, was in progress up to a specific time in the past, and may or may not have continued beyond that point)

As you can see, the past perfect tense is used to describe actions that were completed before a specific time in the past, while the past perfect continuous tense is used to describe actions that began in the past, were in progress up to a specific time in the past, and may or may not have continued beyond that point. It is important to use these tenses correctly and appropriately in order to convey the intended meaning clearly and accurately