善恶之间的界限是可渗透的，任何人都可以跨越。

数据抽象是将特定数据集简化为整体的简化表示。

I always wanted to be a singer, and I focused on that goal, even when others told me I couldn't do it.

When public speaking， pause frequently. Pause before you say something in a new way， pause after you have said something you believe is important， and pause as a relief to let listeners absorb details.