首字母填空,For some time,people have been wond首字母填空,For some time,people have been wondering what u___ can be made of the material.

问题描述:

首字母填空,For some time,people have been wond
首字母填空,For some time,people have been
wondering what u___ can be made of the material.

useful
应该是

use
有一段时间人们一直想知道什么可以作为材料.