Cfxtrjtrk

Conventionally, would can be either the past simple or the past subjunctive of will. To put it very simply, it is best considered past simple if you are looking forward from a past perspective in a story. In that case, it is used in the middle of a narrative that is in the past tense. Both the narrative and would are then simply a description of the past; what would be will in a narrative in the present tense becomes would:

• She said she would succeed. (In direct speech it would be: She said: "I will succeed".)




• He knew they would find him eventually. (In direct speech it would be: He thought: "I know they will find me eventually".)

In most other cases, it is past subjunctive. This tense can be used in several ways, of which the conditional is the most frequent:

• If he were rich, he would still be a
  bastard. (The conditional is used to express that "he will still be a bastard" is only true if the "if" condition is fulfilled.)




• She would like some more tea. (Here
  there is some implied condition, such
  as "if you asked her", "if it were
  possible", "if she were permitted to
  speak", "if it weren't rude", etc.;
  that is why conditional past
  subjunctives are often used to express
  politeness.)

All the above generally applies equally to the other modal verbs, can, shall, and may.

If you say "will you give me some advice?", this is a perfectly fine and polite request, though perhaps a tiny bit old fashioned. It could theoretically be a question about the other person's desire, but context makes it clear that this is not what is intended.

"Would you give me some advice?" is an attempt at even greater politeness, because the conditional makes the request even more tentative, as explained above. Take your pick.

Either would or will work, but you wouldn't change the noun:

Would you give me some advice?

and

Will you give me some advice?

Is “would” the past future tense of “will” or just a modal verb?

Would is the past tense of will in sentences like

He said he would be away for a couple of days.

He wanted out, but she wouldn't leave.

The difference between Would you give me some advice? and Will you give me some advice? is that the first is considered a polite way to ask help, while the second (depending on the context) could be also understood as expressing desire, consent, or willingness.

Will you have a cognac?

Kosmonaut:I don't know where you are
getting these ideas. "I told him that
I would meet him in the city on
Tuesday." — This is a past tense usage
of will. "I couldn't watch my favorite
show yesterday." — This is a past
tense usage of can.

These ideas come from long years of teaching ESL/EFL and from those same long years spent studying the English language. I simply made note that when students followed the rules they produced unnatural English. I made note when students said to me, "why are you saying, "we might [do something] tomorrow" when 'might' is the past tense of may and you're talking about tomorrow"?

Kosmonaut: "I told him that I would meet him in
the city on Tuesday." — This is a past
tense usage of will.

No, it isn't. I certainly agree with you that that's long been what people have been told, but it's simply not true. But I don't suspect that me telling you that, even twice, is going to convince you.

I won't try to give you an example of 'would' as a past tense usage of 'will' because I can't. No English speaker can. It can't be done.

The only part of your quote above that is past/finished is 'told'. I'm making the assumption for the purposes of my argument that we haven't yet come to Tuesday, so the event isn't finished, which is another great indicator that what 'would' is doing here is not describing a past time event which would, of course, then have to trigger a true past tense use.

Another equally valid and grammatical response to what you suggest is 'would' as a "past tense usage of will", could be,

2) I told him, "I will meet you in the city on Tuesday".

Do you agree?

Now, how would 'would' be the past tense of an action that has not yet occurred. Do we ever use a past tense for the purpose of describing an action that hasn't happened?

Moreover, if it was a true past tense, why are we able to use 'will' in 2), above.

In fact, why can we continue to use 'will' for all time, even when and if the action IS ever completed, to describe the direct quote? The reason for that is a simple one; the actions that we take with respect to direct versus indirect speech are done to mark them, not as past or present tense, but as direct [quoted accurately] or indirect [not quoted accurately].

Think of all the times that we [newspapers, people] use these grammatical patterns and we never seek to find out if the action commented on has ever come to pass.

Now, let's say that we have reached Tuesday, and the "I" has met the "you/him". We now have a completed action.

Would any native speaker ever say in order to describe that that action of meeting has been completed,

We would meet on Tuesday. ?

[I'm referring to a usual past tense, not to 'would used in the past for a future'.]

Why does 'would' fail when it comes time to the central purpose of past tense, describing a finished action?

[I'm not ignoring you, Cerebus.]

Yes, How could i know the 'would' is
used as an modal auxiliary or just the
past tense form of the 'will'?

There is a very easy way to tell. Modal verbs have no tense. In modern English, all modal verbs are tenseless. There are no past tense forms or present tense forms. In older forms of English, modals did have tense, so we can accurately refer to modern modals as "historical past tense forms" or "historical present tense forms".

It's easy to prove this because no one can make a sentence in English where any one of the purported past tense modals acts as a real past tense.

Where modals seem like they are being used as a past tense, in reporting speech, they aren't really acting as past tense. They are simply being used the same as the past tense FORM of lexical verbs in a process called backshifting, to signal that the speech is not direct/quoted but rather it is indirect/reported.

The difference between "Would you give me some advice?" and "Will you give me some advice?"
is only one of level of politeness/deference. As the historical past tense forms, in their epistemic [level of certainty] meanings show a greater sense of doubt/certainty, that same doubt/uncertainty carries over to modal deontic [social] meaning so they are considered more polite/more deferential/softer/less direct.