________ about the material,she touched it and learned it felt like silk.

因为这里考你的 是 原因状语从句.
是下面的第一类
一、形容词作状语的情况形容词除了常见的在句中作定语、表语和宾语补足语外,也可像副词一样在句中作状语.
1．原因
Overjoyed,he rushed out of the house．
Much interested,he agreed to give it a try．
Afraid of difficulties,they prefer to take the easy road． 这些前面都不用再加Being
2．时间
Ripe（When ripe）,these apples are sweet．
3．伴随或方式
He spent 7days in the wind and snow,cold and hungry．
Helpless,we watched the house being destroyed before our eyes．
二、可用作伴随状语的几种方式
1．形容词
They all rushed up,eager to help．
She returned to work,unhappy．
2．现在分词
I don't like to sit here doing nothing．
He rushed out,even forgetting to take his overcoat．
3．过去分词
Accompanied by the professor,he spent several days doing experiments one after another．
4．介词短语
I said it in fun．
5．名词短语
Theory should go hand in hand with practice．
6．独立结构
He lay on his back,his hands crossed under his head．
The teacher came in,book in hand．
With the old man leading,they two started toward the mountain．
Now he could walk only with his brother supporting him．我知道可以做状语，你这个答案我也在别处看过了。我的问题是为什么B就不对？你并没有回答我的问题哦。形容词作状语的时候，如果系动词是be动词，be动词都是省略的。除非being ill不是形容词作状语，是动名词做状语。