argue the toss
US /ˈɑːrɡju ðə tɒs/
UK /ˈɑːrɡju ðə tɒs/

1.
争论, 争辩已定的事
to dispute a decision or choice that has already been made, especially when it is too late to change it
:
•
It's no use arguing the toss now, the deadline has passed.
现在争论已经没用了,截止日期已经过了。
•
The manager made his choice, so don't even try to argue the toss.
经理已经做出了选择,所以别想争论了。