Why not just: on jo puoli kahdeksan?
"So on jo puoli kahdeksan" would be the literal translation...
Not really. It is impossible to literally translate the "it" because it's a dummy subject in that sentence, and Finnish does not use nor have dummy subjects.
Seven = seitsemän
Half past seven = puoli kahdeksan
In Finnish, "puoli kahdeksan" means halfway TO eight (7:30) rather than half-past-eight like "half eight" in some dialects of English.
We use the same construction in Russian and I guess the easier to understand this concept translation would be "half of the eighth (hour)"
Why exactly is "kello jo on" instead of "kello on jo" wrong?