Quote Originally Posted by Ramil
no, it would be а о бетоне.
о is pronouced as о in both occurrences.
Just for the record: I don't agree.
"O" is unstressed, thus it sounds like something between "a" and "o". The faster you speak, the more it resembles "a" sound.
Full-blown "o" is possible if you intentionally speak very clearly or slowly (even exaggeratedly so).