I hope you're the only one who knows it.

　　但愿只有你知道這件事。

　　Who knows most says least.

　　懂得最多的人，說得最少。

　　Who knows what they look like?

　　誰知道他們長什么樣子呢？

　　Who knows when we'll be done?

　　誰知道我們什么時(shí)候完成呢？