There are many varieties and grades of paper materials, and whilst it is fairly easy to spot the varieties, it is far more difficult to spot the grades.

纸张材料有许多品种和等级，虽然很容易分辨它们的种类，但要分辨它们的等级就困难得多了。

youdao

There are a lot of materials which can be used for making paper, but the superiority ones are soft wood, cotton and rags.

可以用来造纸的材料很多，但以软木、棉布和碎布为优。

youdao

In order to give us our white paper and card, the makers will add bleach and other materials such as china clay and additional chemicals.

为了给我们提供白纸和卡片，制作商会添加漂白剂和一些其他材料，比如瓷土和其他化学品。

youdao

"The biggest thing was just like this paper airplane, it was a way that you can make something with found materials,cheap paper, scraps,even trash."

VOA: standard.2010.03.17

In addition, in terms of conveying content, we prepared a notebook, where we had all the teaching materials that Professor Low used in this lecture on paper.

另外，从传递信息而言，我们准备了一个笔记本，其中包括Low教授课上,用到的所有教学资料。

麻省理工公开课 - 媒体、教育、市场课程节选

It says the way to reduce paper use lies in cutting consumption in industrialised countries, improving papermaking efficiency, and using more recycled paper and materials other than wood in manufacture.

BBC: Half paper waste 'could be saved'

"Not only are children and young people more likely to read on electronic devices than they are to read paper-based materials but they also do it more often, " said the study.

BBC: Young people 'prefer to read on screen'

These companies are principally engaged in the business of producing raw materials, including paper or wood products, chemicals, construction materials, and mining and metals.

FORBES: Three Unloved ETFs With Extraordinary Returns