Well, it's best in general, for more effective writing, to leave out the "to be" verb (is, has, had) whenever you can. Such as: rewriting the sentence. So, for example: "He had done it" can be transformed into "He did it."
Have + verb = Continuous action in the past with no definite beginning and ending. Such as: "I have skipped rope in my time."
Had + verb = One action in the past with a definite beginning and ending. Such as: "I had walked to the store, but it was closed."
Present tense writing uses the verb tense differently with different points-of-view: If you're doing a THIRD-PERSON point of view, you are to be using past-tense verbs, such as "He walkED to the store." (That example is also a good way of fixing the "Had + verb" example for more effective writing...i.e. getting rid of the "to be" verb.)
If you're doing a FIRST-PERSON point of view, you are to be using the present-tense verb, such as "He walkS to the store," or "I walkED to the store."
SECOND-PERSON point of view would be as such, "You walk to the store."
no subject
Have + verb = Continuous action in the past with no definite beginning and ending. Such as: "I have skipped rope in my time."
Had + verb = One action in the past with a definite beginning and ending. Such as: "I had walked to the store, but it was closed."
Present tense writing uses the verb tense differently with different points-of-view:
If you're doing a THIRD-PERSON point of view, you are to be using past-tense verbs, such as "He walkED to the store." (That example is also a good way of fixing the "Had + verb" example for more effective writing...i.e. getting rid of the "to be" verb.)
If you're doing a FIRST-PERSON point of view, you are to be using the present-tense verb, such as "He walkS to the store," or "I walkED to the store."
SECOND-PERSON point of view would be as such, "You walk to the store."
---
Much blah. It's the writing-tutor in me. ;)