They are the result of a long process of trial and error.

它们是不断的尝试和失败之后的结果。

youdao

This method of manufacture evolved out of a long process of trial and error.

这种生产方法是经过长期的试验和失败获得的。

youdao

It was a long process of trial and error with the collaboration of factories.

这是一个不断试验的过程，当然也不可避免不断犯错误，这需要工厂和我们的通力合作。

youdao

This was a long process of trial and error, of putting together, and looking at backtesting.

FORBES: Use the RCI to Gauge Market Strength