The reason we think the past is fixed once and for all is that there is a boundarycondition at the beginning of time.
原因就是，我们认为过去是曾经确定的，未来全部由自己把握是因为在时间的开始有一个界定的条件。
2
This program begins by first checking a boundarycondition -- whether or not the list is empty.
这个程序首先检查边界条件 —— 列表是否为空。
3
Ordinarily we do not imagine that there is any analogous boundarycondition in the future-entropy continues to grow, but we cannot use that information to draw any conclusions.