The past perfect tense describes something that happened in the past before another action, or before a specific point in time. Typically, the past perfect is used in conjunction with the helping verb “had.” For example: "Had I known you were coming, I would have baked a cake.” An example expressing time would be: “Had you eaten sushi before today?” Past perfect can show duration by showing something that has happened in the past conditional on another acting ending. For example: “By the time we finished our meal, the sun had set.”
Simple Past or Past Perfect
The simple past should be used instead of the past perfect if something has a definite start and stopping point in the past. For example, “She went to the beach yesterday,” is a good example of the simple past tense that describes a past action. “I went to the beach every day last year,” uses the simple past to express a habit or ritual. “I had been at the beach all day before my boyfriend arrived,” uses the past perfect tense, because it describes an action that happened before another one.
Present Perfect or Past Perfect
The present perfect tense can be used to describe a past experience by combining a past participle with have or has. “I have been to this beach often” and “Have you been to this beach before?” are both examples of when you would use the present perfect tense instead of either the past perfect, or the simple perfect tense.