Two questions about this passage

[hirashin]

The Chinese first made paper about 2,000 years ago. It was not made from trees, however, but from some other plants. In Europe, paper was made from trees around 1,100, but it was not commonly used.
For hundreds of years, people in Europe continued to use the skin of some young animals to write on, but they finally found that paper made from trees was the best of all. It soon became popular all over Europe. People outside Europe also learned how to make paper from trees. Since then, forested countries such as Canada, Sweden and Finland have become the most important countries in paper-making.
When we think of paper, we think of newspapers, books, and letters. But there are many other ways of using paper. Only half of the paper that is made is used for books, newspapers, and other printed materials. Every year, more and more things are made from paper. For example, we have chairs, tables, and even beds made from paper. We can wear paper shoes, paper hats, and paper dresses.
The newest thing is a paper house. It is not a toy house for children, but an actual house. It is made from recycled paper, (　A　) it is environmentally friendly. Of course, people can live in it. You can buy a house with a few rooms for about 5,000 dollars. As (B)[ paper / this / building / house ] is not so difficult, it can be also used as a shelter for refugees.

I have two questions about the passage above.

Q1) For (a), which word would be possible, "so", "as", or "but"?
Would either "so" or "as" make sense?
Q2) For (B), please put all the words so that the sentence will make sense. My answer is :
Building this paper house
Are there any other possible answers?

Thanks in advance.

Hirashin

 

[Majestic]

Q1. "So" would be the best choice.

"So" (as in "therefore") implies the following clause is a consequence or a result of the preceding predicate. The quality of the recycled paper makes it also environmentally friendly.

"As" inverts the order of the cause and result, stating the result first and then describing the cause. The material is environmentally friendly as it is made out of recycled paper. In the sample you have given, "as" is an invalid choice because the environmental friendliness of the paper is not the cause of it being recycled.

"But" would only be used in this situation if you were contrasting disparate concepts, or stating a cause with a surprising or unexpected result. In this case, recycled paper and environmental-friendliness are two similar concepts, so using "but" here doesn't make sense.

Q2. I think you have the right and only answer.

 

[hirashin]

Thank you for the help, Majestic. I appreciate it.