Time is still the great mystery to us. It is no more than a concept; we don't know if it even exists.

Time is still the great mystery to us. It is no more than a concept; we don't know if it even exists.

时间对我们来说仍然是一个巨大的谜。它只是一个概念;我们甚至不知道它是否存在。

-- Clifford D. Simak 西马克·克利福德