Definition
The reasons or causes for something.
原因；緣由
I am not entirely clear about the whys and wherefores of this project.
我不完全清楚這個項目的來龍去脈。
Don't jump to conclusions before fully understanding the whys and wherefores of the matter.
在完全了解事情的來龍去脈之前，不要妄下結論。
She always asks about the whys and wherefores of everything, wanting to know all the details.
她總是詢問每件事的來龍去脈，想要知道所有細節。