They act as if they are giving us charity,she says. So really it is not easy.

VOA: standard.2009.08.27

It turns out that getting large molecules like this, particularly large charged molecules like nucleic acids, inside of cells is not so easy.

后来证实,将这样的大分子物质,尤其是像核酸这样带有大量电荷的分子,送入细胞不是一件容易的事

耶鲁公开课 - 生物医学工程探索课程节选

Not so easy to see. All right, but this is actually a great one of those educational moments. This is a great example to think recursively. If I wanted to think about this problem recursively- what do I mean by thinking recursively?

看不太出来，好，但实际上是一个有教育意义的时刻,这是一个很好的关于递归的例子,如果我用递归的思想,去考虑这个问题-,我该怎么用递归去解决这个问题呢？

麻省理工公开课 - 计算机科学及编程导论课程节选