an unknown quantity

汉语翻译

未知量, 难预测的事

例句

The new teacher is still very much an unknown quantity but we have hopes that he will be a valuable member of our team.新教师是谁现在还难以预料，但我们希望他会成为我们队里的重要一员。The new sales director is still a bit of an unknown quantity.新来的销售部主任大家还不大了解。