Answer:
In the book Harry Potter and the Sorcerer's Stone by JK Rowling Harry is first I,troduced to the magical world when he enters Diagon Ally. This ally is a bright cheerful area full of energy he seas so many new and diffrent things described in great color and hears people talking about strange things. It is a great way to show the reader how this world is so magical and new to Harry.
“This could use more explanation/length.”
Answer:
Children is the subject of the sentence.
Explanation:
The children are the subject of this sentence, they are doing an action. The children do two actions, the children<em> ran</em> and the children <em>sat</em>.
I may not have understood correctly what the question is asking, so I hope this helps anyway.
In terms of the first question, "They" would be an objective pronoun, but it should be noted that this does not have to be so. for the second, the answer is "my".