You would say that the race comes down to the wire (not that the result is down to the wire).

“day by day there are many sport advances” can be, “because the sport is advancing every day.”

And you might enjoy this episode: New generation of ‘super-shoes’ help marathoners break records

Love those games!

You said it right the first time. “We have a lot of fun until the very end.” If you were out playing now, you could say, “we are having a lot of fun”, but that wouldn’t work with “until the end.”

By the way, in speech, it would be very common to say (out loud) “till the very end” but it’s not very common to write “till” – you would almost always write “until”.

Love it! Great example. With “decided” you can say, “…are decided at the last minute” or “…are decided at the very end.” But with “down to the wire,” you would usually say “come” or “go” (come is more common). So you can say, “Most of the games come down to the wire.”

Or should I say: We are having a lot of fun till the very end? What option is better?

You’re doing great!

Great example