Q

What goes on four legs in the morning, on two at noon, and on three in the evening?
什么走路开始用四条腿，后来用两条腿，最后用三条腿？

A

People. They crawled when they were babies and walked with two legs before they had to rely on a crutch in old age.
是人，他们刚生下来的时候用四肢爬行，后来用双腿走路，老年时又不得不依靠拐杖走。

点睛一笔

问题中in the morning（在早晨），at noon（在中午）和in the evening（在晚上）三个时间短语并非表示一天中的时间，而是表示人的“婴儿时期”“青壮年时期”和“老年时期”。本题是事物谜，也叫作描述性谜语。谜面通常是用比喻、暗示或其他方法来描述所猜谜底的特征。