It happened—whether by accident or design —that the two of them were left alone after all the others had gone.

碰巧—不知是偶然还是有意安排—其他人走后，只剩下了他们两个人。

《牛津词典》

It was hard to know whether it happened by accident or by design.

很难知道这是偶然发生还是有意为之。

youdao

Since we decide by design or accident to bring children into the world, with that comes the duty to care for them.

既然我们有意或无意的决定让孩子来到这个世界，那我们就有义务照顾他们。

youdao

Mr. Haslam fell into interior design by accident.

WSJ: 20 Odd Questions: Nicky Haslam

Whether by design or by accident, Santorum is capitalizing on our collective exhaustion from living in an ever-changing technologically-mediated future.

FORBES: Santorum's Rise and the Shocking Power of Future Shock

There was a lack of controls for risk: "The risk function was a cardinal area of weakness, " and this was "a matter of design, not accident".

BBC: Carrying on banking