英语选择题,帮忙解析一下

英语选择题,帮忙解析一下
1.In the reading room,we found her _____at a desk,weith her attention _____on a book.
A.sitting;fixingB. seated;fixed
答案是选B的,为什么第一个空要用过去分词呢?
2.After taking your medicine,the pain in my chest was_____
A.goneB.away
答案是A,为什么不能选B?
3._____to his research,he hardly has dinners with his family.
A.Devoted B.To devoteC.Devoting
答案是选C,可是前面的一部分不是伴随状语吗,而且这里好像是表被动
4.He had to take the medicine three times a day,in order to be _____the pain in the leg.
A.far away B.away from C far from D.free from
答案是D,请解析下其他选项不能选的原因.
5.He asked me _____with me.
A.what wasthe matterB.what the matter was
为什么B选项中的句子不对呢?what在从句中不是充当宾语吗?
O(∩_∩)O谢谢