Could you offer a help about these two sentence(with the same meaning) ?

I understand such sentence as the following is correct :
On the stairs was sitting a small dark-haired girl.(= Sitting on the stairs was a small dark-haired girl. )
But I don't know whether or not these two sentences are correct:↓

1.In Tom's room was reading that book Mary.
2. Reading that book in Tom's room was Mary.
Are the two sentences both correct?

And by the way,what's about these two sentence?↓
(a).In Tom's room was reading that book in a distracted manner Mary.
or,
(b). Reading that book in a distracted manner in Tom's room was Mary.
(Note: the basic meaning is :
Mary was reading that book in a distracted manner in Tom's room.)

Question

Could you offer a help about these two sentence(with the same meaning) ?

I understand such sentence as the following is correct :
On the stairs was sitting a small dark-haired girl.(= Sitting on the stairs was a small dark-haired girl. )
But I don't know whether or not these two sentences are correct:↓

1.In Tom's room was reading that book Mary.
2. Reading that book in Tom's room was Mary.
Are the two sentences both correct?

And by the way,what's about these two sentence?↓
(a).In Tom's room was reading that book in a distracted manner  Mary.
or, 
(b). Reading that book in a distracted manner in Tom's room was Mary.
(Note:  the basic meaning is :
Mary was reading that book in a distracted manner in Tom's room.)

Answer

1. In Tom's room was Mary reading a book.
2. Mary was reading a book in Tom's room.

Or
1.Mary was distracted as she read that book in Tom's room.

2. That book distracted Mary as she read in Tom's room.

Sometimes words havw to be moved around and others inserted to make a sentence flow. I hope that helps.

Answer

B is definatley a better option, but I think your example of what it's supposed to be is the best way to phrase it.  The most important difference I think is that there's no reference that MARY is the subject of the sentance.  Mary was reading.... is a lot more clear as to what's happening as opposed to putting the subject at the end.  I hope that helped!

Answer

Those first pair of sentences are not the same. The first sentence does not make sense. And sentence a . Also is not grammatically correct.