Regulus survived only a few days after defying Voldemort (reason unknown) (HBP6).

雷古勒斯在不服从伏地魔之后只活了几天(原因未知)(HBP6)。

youdao

No. 2 engine intensive vibration (severe vibration), reason unknown, we might shut down engine anytime.

第二发强烈抖动(严重抖动)，原因不明，我们随时可能关闭发动机。

youdao

The Republicans, for some unknown reason, decided to pass on fully emulating that system year.

FORBES: Obama's Not-So-Secret Weapon: Will He Use It to Help Power His New Mandate?

For some strange and unknown reason, the Small Business Administration has changed how it defines government support of small businesses, which will inadvertently destroy many small businesses, especially those supported through the Department of Energy.

FORBES: The Small Business Administration Decides to Hurt Small Businesses

For some unknown reason, it tries to force me to use Albany, NY as my departure airport for every search even though I do not live near Albany and have never flown in or out of the airport.

FORBES: Google Flights? Not Ready For Prime Time.