非機遇原因;
例句:
1.
The unknown and unpredictable element in happenings that seems to have noassignable cause.
偶然性在似乎無因可查的事件中末知和不可預測的成分。
2.
It is noteworthy in this scenario that the original, thorough laboratory investigationfailed to find any assignable cause.
值得註意的是此假想有壹個前提，即在初始的完整化驗室調查中，並未發現任何可歸結原因。