So I am going to do a little (or a lot) of explanation about the verb tenses:

There are twelve possible verb tenses. The verb tenses are categorised according to the time frame: past tense, present tense, and future tense. Within each of these there are additional subdivisions: simple, progressive, and perfect, and perfect progressive.

The four past tenses are

the simple past - I went
Note that I went can never be present tense, just as I go can nnever be past tense.
the past progressive - I was going
the past perfect - I had gone
the past perfect progressive - I had been going
Note that the past perfect and past perfect progressive are a past not present tenses -- that idea is that the speaker in the past was the state of being gone or having been going.

The four present tenses are

the simple present - I go
the present progressive - I am going
the present perfect - I have gone
the present perfect progressive - I have been going
Note that the present perfect and present perfect progressive are a present not past tenses -- that idea is that the speaker is currently in the state of having gone or having been going.

The four future tenses are

the simple future - I will go
the future progressive - I will be going
the future perfect - I will have gone
the future perfect progressive - I will have been going

Verb Tense: Aspect
Verb tenses are also categorised according to aspect. Aspect refers to the nature of the action described by the verb. There are three aspects: indefinite, complete, continuing.

The three indefinite tenses, or simple tenses, describe an action but do not state whether the action is finished:

the indefinite past - I went
the indefinite present - I go
the indefinite future - I will go
The indefinite aspect is used when the beginning or ending of an action, an event, or condition is unknown or unimportant to the meaning of the sentence. The indefinite aspect is also used to used to indicate an habitual or repeated action, event, or condition, for example: I go to church every Sunday.

The three perfect tenses, describe a finished action:

the complete past - I had gone
the complete present - I have gone
the complete future - I will have gone
The complete aspect indicates that the end of the action, event, or condition is known and the is used to emphasise the fact that the action is complete. The action may, however, be completed in the present, in the past or in the future. Note that the complete past sentence: I had gone to church every Sunday until I stopped while it will understandably confuse many people is still in the past tense.

The three progressive tenses describe an unfinished action:

the past progressive - I was going
the present progressive - I am going
the future progressive - I will be going
The continuing aspect indicates that the action, event, or condition is ongoing in the present, the past or the future. Note that in the sentence: I was going to church every Sunday again may confuse many people as to tense because the action was ongoing, but is indeed past tense.

It is also possible to combine the complete tenses and the incomplete tenses, to describe an action which was in progress and then finished:

the past perfect progressive - I had been going
the present perfect progressive - I have been going
the future perfect progressive - I will have been going
Note that a sentence such as I had been going to church when I was hit by a car is nicely complicated as to tense and sure to confuse many of us, but is past tense.

The Function of Verb Tenses

The Simple Present Tense

The simple present is used to describe an action, an event, or condition that is occurring in the present, at the moment of speaking or writing. The simple present is used when the precise beginning or ending of a present action, event, or condition is unknown or is unimportant to the meaning of the sentence.

Here is an example with the verb in italic:

Jane waits patiently while June buys the tickets.

The simple present is used to indicate a habitual action such as:

James polishes the silverware every Saturday.

The simple present is used when writing about works of art.

The opera ends with an aria.

The simple present can also be used to refer to a future event when used in conjunction with an adverb or adverbial phrase,.

School ends next week.

The Present Progressive

The simple present and the present progressive are sometimes used interchangeably. The present progressive emphasises the continuing nature of an act, event, or condition.

Peter is dusting all the furniture in the living room.

The Present Perfect Tense

The present perfect tense is used to describe action that began in the past and continues into the present or has just been completed at the moment of utterance. The present perfect is often used to suggest that a past action still has an effect upon something happening in the present but it is still present tense.

They have not delivered the books we need.
Note that this suggests that the books were not delivered in the past and that they are still undelivered.

The Present Perfect Progressive Tense

Like the present perfect, the present perfect progressive is used to describe an action, event, or condition that has begun in the past and continues into the present. The present perfect progressive, however, stresses the on-going nature of that action, condition, or event.

They have been producing this series book for five years.
Note that this implies that they started producing it in the past, are still producing it and will continue to do so in the future but the tense is present tense.

The Simple Past Tense

The simple past describes an action, an event, or condition that occurred in the past, sometime before the moment of speaking or writing.

Amanda grabbed the sword and killed the monster.

The Past Progressive Tense

The past progressive tense describs actions ongoing in the past. These actions often take place within a specific time frame. While actions referred to in the present progressive have some connection to the present, actions referred in the past progressive have no immediate or obvious connection to the present. The on-going actions took place and were completed at some point well before the time of speaking or writing. In spite of their being ongoing, it is important to note they are past tense.

The monster was leaping along the top of the wall.

This describes an action that took place over a period of continuous time in the past. The monster's actions have no immediate relationship to anything occurring in the present.

The Past Perfect Tense

The past perfect tense describes to actions that took place and were completed in the past. The past perfect is often used to emphasis that one action, event or condition ended before another past action, event, or condition began.

After we located the monster that Julian had talked about, we killed it.
Here "had talked" precedes having "located" or "killed" the monster. Both actions took place sometime before the moment of speaking or writing.

The Past Perfect Progressive Tense

The past perfect progressive indicates that a continuing action in the past began before another past action began or interrupted the first action.

Jane had been reading fantasy novels for several years before she discovered the works of Christopher Paolini.

In this sentence the act of discovery ("discovered") occurred in the past but after the ongoing and repeated action of reading ("had been reading").

The Simple Future Tense

The simple future is used to refer to actions that will take place after the act of speaking or writing.

You will feed the cat tonight?

The Future Progressive Tense

The future progressive tense describes actions ongoing in the future. The future progressive is used to refer to continuing action that will occur in the future.

The smith will be working on the sword for the next week.

The Future Perfect Tense

The future perfect describes an action that will be completed sometime in the future before another action takes place.

The physician will have seen on 6 patients before she goes to the hospital.

The Future Perfect Progressive Tense
The future perfect progressive tense indicates a continuing action that will be completed at some specified time in the future. This tense is not much used.

I will have been writing fiction for three years by the end of this year.
In this sentence, the future perfect progressive is used to indicate the ongoing nature of the future act of the studying. The act of studying ("will have been writing") will occur before the upcoming end of year.

I hope this clarifies some of the verb tense confusion. There is an excellent website run by Purdue University that has on-line handouts on not only verbs, but almost any grammar subject. They are will written and easy to understand even for us non-grammarians. If you have any confusion over verbs or my own personal bugaboo, commas, or other grammar problems I recommend them.

You can find them at http://owl.english.purdue.edu/handouts/grammar/

Thanks and good writing.

Edit: Hopefully not too many typos lol Just fixed one.

However, I did cheat and refer to my trusty Elements of Style while typing it.

I should have mentioned in my post that I checked my definitions and lifted some of the verbiage in the descriptions of tenses from that particular work.

And thank you, Matt. I felt it was time for more light and less heat on the grammar issue.

[This message has been edited by JeanneT (edited July 08, 2007).]

I've seen several other things like this in various works and they always bug me.

I hate the phrase "to fell a tree".

The above attempt at dialect reminds me, I just finished reading an excellent western novel by Stan Lynde that broke all of the rules of grammar to great good effect.

I wonder, if you don't absorb the rules of grammar in childhood, can you do so as an adult through conscious effort? Maybe, if you read enough and have a good ear.

I never seem to master the difference between "that" and "which".

:::::Is "his heart speeded up" ok? I want to say "his heart sped up".

The difference between "sped" and "speeded" is one of usage, and has nothing to do with grammar. The two words are synonyms. To my ear, "speeded" is better if you exceed the speed limit, otherwise I like sped.

My spellchecker doesn't know "speeded", but my Oxford American Dictionary allows it as a synonym for "sped".

Rick said, 'I never seem to master the difference between "that" and "which".'

I don't know if you really want to fall into the Language Log -- it always takes me quite a while to climb back out again -- but it will tell you that you don't really have to know the difference. More specifically, it will say, "The notion that phrases like any book which you would want to read are ungrammatical is so utterly in conflict with the facts that you can refute it by looking in... well, any book which you would want to read." And then it will provide lots of corroborating evidence. (These are the same people who call The Elements of Style "Strunk and White's poisonous little collection of bad grammatical advice". Fascinating reading, this blog.)

That said, if you want to quickly find out which one most grammar wonks think you should use, try removing the phrase that comes after "that" or "which" and see if you really must have it. If you could live without it, use "which" and put it in commas; if you really need it, use "that" and leave the commas out.

"The cup that I bought yesterday cost me ten dollars." I have many cups, but the particular one that I bought yesterday cost me ten dollars.

"The cup, which I bought yesterday, cost me ten dollars." I am discussing one cup, and it cost me ten dollars; for some reason, I find it relevant to tell you that I bought it yesterday.

The first example could have been written, "The cup which I bought yesterday cost me ten dollars." Although many people will get irritated with you and say that your grammar is wrong (I once would have), the mavens at the Language Log point out that much great literature has been written using that construction. Since I'm trying to avoid annoying people as much as possible, I always use the "correct" constructions, as given in the examples.

Regards,
Oliver