What is a feather,but you can't hold it for about 10 minutes?Why?

问题描述:

What is a feather,but you can't hold it for about 10 minutes?Why?
What is lighter than a feather,but you can't hold it for about 10 minutes?Why?

什么比羽毛更轻,而且你仅仅只能拥有它十分钟左右?为什么?
snow flake
(Ps:看着有点晕,看了相关的一个帖子,才反应过来哈^_^)