题目内容：

    Elephant, horse and cow wastes could be endless sources for a key element needed to make paper. It is good news for some nations where trees are scarce while animal wastes come in especially handy.

The idea for the unusual use of elephant and cow wastes first came to mind when researcher Dr Alexander Bismarck noticed something strange about goat wastes while vacationing in Greece. He observed some goats eating summer-dry grass and came to an interesting conclusion about what they digest.

Dr Bismarck said： “I realized what comes out in the end is partially digested plant matter so there must be cellulose （纤维素）there". Animals eat dry grass containing cellulose, chew it and digest it in their stomach and then produce wastes. Up to 40 percent of those wastes are cellulose, which is easily accessible. Therefore, making paper from the partially digested            material would take much less energy than using raw wood. Additionally, it would require fewer chemical treatments.

This supply of raw material is plenty： parks in Africa that are home to hundreds of elephants produce tons of wastes every day, and enormous cattle farms in the US and Europe produce mountains of wastes.

In order to make paper, the material must be processed with a special method. But it requires little because there is no need to break it down into small parts for use in paper, in contrast to conventional methods which need a lot of energy to break down wood.

Using wastes, we can reduce the number of steps needed in papermaking, simply because the animal already chewed the plant and attacked it with acid in their stomachs. You inexpensively produce a paper staff that has the same or even better properties than that from wood, with lower energy and chemical consumption.

1.What is mainly talked about in paragraph 2?

A.The observation of goat wastes. B.The usage of animal wastes.

C.The origin of the unusual idea. D.The vacation spent in Greece.

2.Animal wastes can be used to make paper mainly because ________.

A.they will never run out B.they are easy to access

C.they are partly digested D.they contain much cellulose

3.What is the advantage of making paper from animal wastes?

A.It is more profitable. B.It is energy-saving.

C.It needs less material. D.It fits all parts of the world.

4.What is the probable explanation of the underlined word “attack"?

A.Treat. B.Mix.

C.Clean. D.Protect.