没有说明书——这只是一个反复试验的问题。

There aren't any instructions with it - it's just a matter of ___trial ___and ___error.

与其向他人学习，你必须通过反复试验来发现最佳方法。

Instead of learning from others, you have to discover the best method through ___trial ___and ___error.

掌握一项新技能通常涉及一个反复试验的过程。

Mastering a new skill often involves a process of ___trial ___and ___error.