1、Rather than re-explain them every time they're used, we document them as distinct data types.
我們將這些數據類型（數值和字符串）列表，這樣在你使用這些數據類型的時候可以更加方便。

2、OK, so maybe I should re-explain that again.
也許我應該重新解釋一遍。

3、Let me re-explain quickly how I got a normal vector for the cylinder.
我來再次解釋一下如何得出這個圓柱面的法向量。