Happenstance Learning Theory偶然学习理论
Planned Happenstance Theory性理论;计划性巧合理论
Whether planned or happenstance无论是否机缘巧合
N-UNCOUNT（不可数名词） If you say that something happened by happenstance, you mean that it happened because of certain circumstances, although it was not planned by anyone. 偶然情况; 巧合 [书面][also 'a' N, oft 'by' N]
I came to live at the farm by happenstance.
我到这个农场来生活纯属偶然。