"Would be" for past usage

She was about seventy when she died. .......

as far as I know ' would be ' is for the future

You might hear people say something like that, but only in conversation, sort of "thinking out loud". People often do not say all of the bits of a verb that you would need in writing!

You are likely to hear it pronounced like this though:

"She'd a bin about" 

meaning she would have been about ..

Only for the future?

She would be about sixty now.

Do you mean in only in the "conversational registers"? Many of the texts below do seem to be conversational.

I would be about 10 or 11 years old, and the biological urge was beginning to stir in my blood, though, truthfully, I had my first sexual intercourse at the age of 19.
-----------------------------------------
Harlow Study Centre: interview (Leisure). Recorded

It seems that two of these sources ARE transcripts of conversation. I'd think only relevant to distinguish a style as "conversational" when it started life as a written form. These 2 examples started out as spoken forms.

As for the notion of future, for the original poster, it seems your answer is that "would be" is used more flexibly than grammar guides can indicate, especially in

That's got me a little confused. Could you expand on it?

Cheers

R

@ milky - I was responding to how you use the term conversational register.

My use of the word "register" is perhaps a bit narrower than yours. I would only say "this is conversational register" when describing the style of a piece of WRITING. It seems slightly redundant to classfiy spoken material as converstional "register" - it just IS conversation.

I then went on to s

Would you term business presentations, university lectures and political speeches as conversation?

Oh noooh Am I reading what I think I am reading? You wouldn't do that, would you?

conversation is supposed to be mutual, isn't it ?