0 used to ask or talk about the reasons for something -- почему?
1 used to make a suggestion -- почему бы тебе не .../почему бы не сделать что-либо?
Why not give it a try?
Why don't you come with us?
2 used to agree with something that someone has suggested -- почему бы и нет?
The diversity of themes covered in the papers is the reason why this seemed to be such an eclectic mix.
However, if something is too complex, or is perceived to be too complex, then why should biologists bother?
Why then were those other thirty also quashed?
So why has such a synthesis been so slow to develop?
Even so, an explanation why just these symptoms co-occur would be welcome.
Now there is no reason why they could not at the same time derive symbolic or evidential value from something else than these outcomes.
But why exactly is this supposed to be a problem?
It also demonstrates why that process took almost twenty-five years to begin.
