As we all know, this only works if there is a pointee, which kind of gets back to rule number one.

众所周知，只有当有指针数据时，这个才起作用，这有点像第一条规则。

哈佛公开课 - 计算机科学课程节选

Synthesis always occurs in one direction and that makes sense to you now because you know there's a directionality and the chemistry is different going one way than the other and this DNA polymerase only works on the chemistry going in one direction.

NA复制过程是单向的,现在你们该明白原因了,因为DNA单链有方向性,DNA在两个方向上化学性质不同,DNA聚合酶,只在一个方向上起作用

耶鲁公开课 - 生物医学工程探索课程节选