题目内容：
There are a lot of materials which can be used for making paper， but the superiority ones are soft wood， cotton and rags. 参考答案：
答案解析：
简答题：There are a lot of materials which can be used for making p
- 题目分类：英语六级
- 题目类型：简答题
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If the lignin is removed from the paper， the paper will be
If the lignin is removed from the paper， the paper will be more expensive.
Acid is particularly harmful to photographic materials.
Acid is particularly harmful to photographic materials.
7
7
―1，2，1，9，100，（ ）
―1，2，1，9，100，（ ）A．81 B．360 C．10000 D．1 1881
The author would probably consider research about the effec
The author would probably consider research about the effects noise has on peop