承B2 或者說
[something(看前面你提到哪方面的事情)] is unpredictable and changeable. As for a feasible answer to this question, time will tell.
或者 The exact answer will only be known in the future.
僅供參考,我英文也不是很強... 不過我覺得像是 We think that / I think這種不用特別寫出來
我個人會說 It’s hard to know the answer before the future comes.
我覺得這樣聽起來比較順
如果你真的想用exactly 的話我會說 it’s hard to know what exactly the answer is before the future comes.