I have suffered and despaired and known death and I am glad that I am in this great world.

布莱克-斯科尔斯公式的美妙之处在于它仅依赖于一个不可观测的参数，即股票的波动率。

To understand the meaning of a sentence， we must consider the speaker's intention and the context of the utterance.

做好研究的秘诀是始终保持轻微的工作不足状态。因为无法浪费几个小时，你可能会浪费数年时间。