[Muhammad Razzaq]

Q. Why do we call a tense "Indefinite" -- the present indefinite, the past indefinite and the future indefinite? Please give a detailed answer if possible? Thanks

[susan53]

We don't. I don't know where you got these terms, but they are not standard.

A tense is a verb form formed by inflection - ie a change to the form of the verb itself. That means there are only two tenses in English :
present tense - eg live can be live or lives; be can be am,is, are.
past tense - live changes to lives, see to saw, be to was/were.

All verb forms also have aspect - simple, progressive , perfect. Simple aspect is really the absence of aspect - the verb is formed by tense only. Continuous aspect is formed by using the auxiliary verb be + present participle main verb. Perfect aspect by auxiliary have + past participle. In both cases, it's the auxiliary which carries the tense indications.

Verb form names indicate both the tense and aspect they carry. Thus we can have verb forms like :
present simple : I live in Milan
past perfect : I had never seen one before
present perfect continuous : I've been expecting you.
and all the other possible combinations - present progressive, past simple, present perfect progressive etc.

These are the standard terms.

English therefore has no future tense - there is no way of indicating future time by verb inflection. Instead, we use a variety of verb forms which tell us how the speaker sees the future. The one often seen as "the" future (though it's not) is the modal verb will, which can combine with various infinitives (simple, perfect, progressive) to express a prediction or the speaker's volition. This was discussed in this thread. But notice it is neither "the" future (there are many other ways to express future time in English) nor always "future" - it can be used to make predictions/deductions about permanent, present and past events too. Will expresses prediction/deduction - not time. As is true of all the modal verbs in English.