Question

Correct the text by inserting one comma.

Until all of the votes are counted we won't know who has won the mayoral
election

Answer 1

Until all the votes are counted, we won’t know who has won the mayoral election.

You put the comma there, because there is a pause in between those two(counted and we).

Answer 2

Until all of the votes are counted, we won’t know who has won the mayoral election.