What can be found once in every miute,twice in every moment,but not once in a thousand years?

问题描述:

What can be found once in every miute,twice in every moment,but not once in a thousand years?

the letter M
字母 M

m
minute里有一个m
moment里有两个m
而 a thousand years中没有m

是字母M
miute和moment都有字母M,而thousand 中却没有!