Much can often be learned by the repetition under different conditions, even if the desired result is not obtained.

Much can often be learned by the repetition under different conditions, even if the desired result is not obtained.

即使没有得到预期的结果，在不同的条件下重复也常常可以学到很多东西。

-- Archer John Porter Martin 阿彻·约翰·波特·马丁