TO BE verbs & their forms - SC Guide

[mbolisetty]

Bumped into many times the phrase "to be" verbs & "various forms of to be verbs"

My questions regarding TO BE verbs,

1) What exactly are "to be" verbs ? (I know that, is/am/was/were/be/been/are are TO BE verbs. But they have nothing to do with "TO" ?

2) What is meant by "various forms of TO BE verbs" ?

3) What is the difference between linking verbs & to be verbs ? If there is difference, where linking verbs are used & where to be verbs are used.

Though the term "TO BE" verbs "Linking Verbs" are often used in SC guide, they have not been explained in detail.

[esledge]

Perhaps a more practice way to think of the "to be" verbs is as "verbs that indicate existence." Correct, it isn't purely about the "to" or the infinitive form, as you can have existence in any tense:

I think, therefore I am.
I thought, therefore I was.
I will think, therefore I will be.
I have thought for years, therefore I have been for years.
I was born to think, therefore I was born to be.
etc...(I may be getting carried away!)

The various tenses are what is meant by "the various forms of 'to be' verbs."

On a quick skim, I could not find a reference to "linking verbs" in our guide, and I have to admit I don't use the term regularly. Can you give a more complete quote, or a page number?