这些名词均有“谜、难题”之意。
puzzle : 语气较强，指复杂令人费解的情况或问题。
- a crossword puzzle
纵横字谜 - a book of puzzles for children
儿童谜语书 - My sister puzzles me and causes me anxiety.
我妹妹总让我捉摸不透，弄得我焦虑不安。
mystery : 指常人难以认识其起因或性质的奥秘，或指有意不让人理解的奥妙。
- It is one of the great unsolved mysteries of this century.
这是本世纪尚未解开的大奥秘之一。 - Their motives remain a mystery.
他们的动机仍然是个谜。 - It's a complete mystery to me why they chose him.
我真无法理解他们为什么会选他。
riddle : 指供人猜的谜语游戏，也可指终究会有解答的难题。
- Can you answer this riddle?
你能猜出这个谜语吗？ - to solve the riddle of the Sphinx
解开斯芬克斯之谜
problem : 指有待探讨的疑难问题，也可指令人困惑的情况。
- Unemployment is a very real problem for graduates now.
现在，失业对大学毕业生是个实质问题。 - mathematical problems
数学题
