Example: Q1: Have you ever been in Venezuela? <--Present perfect A2: Yes, I visited Venezuela in the 1970 for ten days. <--Simple past Q3: Had you studied any Spanish before your visit? <--Past perfect A4: Yes, but I hadn't retained much. <--Past perfect Q5: Have you studied any Spanish since then? <--Present perfect A6: I have studied Spanish for about a year-and-a-half now. <--Present perfect Q1 asks about any year from 1945 (about when I was born) to 2015 (now). Q2 talks about the specific year, 1970, when I visited Venezuela. Q3 asks about 1945 to 1970. A4 talks about 1945 to 1970. Q5 asks about 1970 to 2015. Q6 talks about 2013, 2014, 2015.

Past Perfect very easy - Had + 3rd form of verb(had gone,had done,had eaten) Use when you have 2 actions in the past.First action- past perfect.Second action past simple for example After HE HAD EATEN his breakfast,he WENT to school. She HAD FINISHED her homework before she called her friend.

When the verb "have" and its forms "had" and "has" is used as an auxiliary verb to form a perfect tense, you don't use "did" So I have done, I had done. When the verb "have" is used on its own to mean "possess" you can use it, but it's not a perfect form then. I did have a book.