All comers to the Sphinx were asked a riddle, and failure to solve it meant death.

所有来到斯芬克斯面前的人都被问了一个谜语，解答不了就意味着死亡。

《柯林斯英汉双解大词典》

Nature is indeed like a riddle, some areas of which are beyond the reach of science and technology, at least in the foreseeable future.

大自然确实像一个谜，其中一些领域是科学技术无法触及的，至少在可预见的未来是这样。

youdao

My discovery of Mary Jackson was, as a matter of fact, a gift from a friend; years ago I was given a copy of Tell Me A Riddle.

事实上，我发现玛丽·杰克逊是因为一位朋友送给我的礼物；几年前，有人给了我一本《告诉我一个谜语》。

youdao

Relenting, the Rabbi finally said that if the young man could unravel a riddle he would accept him as a student.

FORBES: The Rabbi's Four Leadership Lessons, Part 1

Bankoff is one of the few digital publishers who seem to have cracked a riddle: How do you produce quality content that will also make money?

FORBES: Meet The Digital Upstart That Thinks Millions Of Rowdy Fans Are The Future Of The Web

Berlin (CNN) -- The story of the so-called Forest Boy -- a riddle that has perplexed people in Germany and elsewhere for months -- is a lie, police in Germany said Friday.

CNN: Police: 'Forest Boy' story is a hoax