You never can tell.

• 难说；没法预料

You never can tell.的用法和样例：

例句

1. The significance of these papyri finds can scarcely be over-exaggerated.
   发现这些蒲草纸的重要性怎么夸张都难说过分。
2. Natural, the Raptor can definitely win more competitions in this season, but in the playoff, all became difficult to say.
   理所当然，猛龙队在这个赛季肯定能赢下更多的比赛，但在季后赛，一切又变得难说了。