Of the blood that has to be destroyed, almost half is caused by the presence of Hepatitis B, Hepatitis C,and syphilis, while the other half is due to problems in the collection process.

VOA: standard.2010.06.04

That is basically saying, given some collection of data, I want to have again a looping mechanism, where now my process is, walk through this, the collection one element at a time. And for that, we have a particular construct, called a FOR loop.

现在我的过程就是,通过一个个访问这个集合中,的元素的方式，来遍历这个集合,为了达到这个目的，我们有一个特定的结构，成为FOR循环。

麻省理工公开课 - 计算机科学及编程导论课程节选