Doctor Guay says the problem in sub-Saharan Africa is the limited availability of anti-retroviral drugs.

VOA: special.2009.07.29

OK. And then the exponentials, as you saw is when typically I reduce the problem of one size into two or more sub-problems of a smaller size.

好，然后说到指数级，正如你所见，典型的例子是,我讲一个问题分解成为,两个更小规模的子问题。

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