snowball's chance in hell字面意思雪球进了地狱，引申为希望不大；毫无机会；机会渺茫。

【例句】
She doesn't have a snowball's chance in hell of winning the race after falling on the last lap.
她在跑到最后一圈时摔倒了，因此她赢得比赛的机会渺茫。

He doesn't have a snowball's chance in hell of getting a date with that girl.
他笃定没有机会跟那位女孩约会。