Consider this phrase:
Deconstruction of the above phrase yields:
Now is twenty minutes before (event).
(Q1) Can I reconstruct the statement using 後 in this manner?:
今は後で(event)に二十分がある。(I'm not sure if I used に correctly here)
(There are twenty minutes from now to (event)).
今は and (event) be elided once the context is set? That is to say
後二十分がある are acceptable phrases?
I think that (event) cannot be elided to form
二十分前です and yet retain the meaning. By itself the phrase would mean "(it was) twenty minutes ago" and would be too vague to be useful to specify (event) in relation to "now".