Past Indefinite, Past Continuous, Indirect speech
1. A knock at the door aroused Martin. He was thinking about Joe and wondering where he was
, as he told the one
, standing behind the door
, to come in.
* Punctuation is weird, but the grammar is good! Good job.
* You should remove all the commas in the second sentence to make it more correct. The phrase "standing behind the door" is better without the commas in this context. As for the comma after "where he was," remember F.A.N.B.O.Y.S. The words "For, And, Nor, But, Or, Yet, So" get a comma before them. "As" does not need a comma before it.
2. She said that no one knew she was there. Martin asked her what she had said. She repeated her words and added that she had saw seen him come in, waited a few minutes and came into the room too.
* This one either needs to be "she had seen" or just "she saw". Either is fine, but I'll go with "had seen."
3. Martin said that he hadn't changed since her mother had broken their engagement. He hadn't become [even] a bit more eligable eligible for Ruth, and she hadn't even bothered to visit him when he had been starving.
* You don't necessarily need to add the word "even," but I think it sounds a little more natural here, though.
* The other rule that applies to F.A.N.B.O.Y.S. is that you shouldn't start a sentence with them, so I would connect the last two sentences with a comma. (In conversation, it's totally fine to start a sentence with "for and nor but or yet so," but in writing it is bad practice. Sometimes authors will do this for effect, but in formal writing this is not good.
