现在的作业本一般是用木材等原材料加工而成的,而我国的木材资源十分短缺。为了节约资源、保护森林,我要发明一种会定时消失的墨水。这种墨水按使用时间分类,你可以选择一个月后消失的墨水,也可以选择半年或一年后消失的墨水。到时墨水会自动消失,作业本就可以重复使用啦!指导 The current homework is usually made of wood and other raw materials, while China's timber resources are in short supply. In order to save resources and protect the forest, I want to invent a kind of ink that will disappear from time to time. This ink is classified according to the use of time, you can choose to disappear after a month of ink, you can also choose to disappear six months or a year after the ink. When the ink will automatically disappear, the job can be repeated use! Guide