Убывала

5 Вода́ постоя́нно убывала до деся́того ме́сяца;

5 Water constantly убывала [before, until] [tenth, the tenth] months;

в пе́рвый день деся́того ме́сяца показа́лись верхи гор.

[at, in, of, on] [first, the first] day [tenth, the tenth] months [showed up, they showed up] верхи mountains.

And the waters continued to abate until the tenth month;
in the tenth month,
on the first day of the month,
the tops of the mountains were seen.
Genesis 8:5 ESV

And the waters decreased continually until the tenth month:
in the tenth month,
on the first day of the month,
were the tops of the mountains seen.
Genesis 8:5 KJV