direct speech: He said to the judge," I did not commit this crime.
Indirect speech(book answer): He told the judge that he had not committed the crime.
Here book changes this into the.
In many instances i found that This was changed into That.for example this week into that week.
Direct speech: He said," I shall do this tomorrow."
Indirect speech(book answer): He said that he should do it the next day.
In #2 book changes this into it.
In three different sentences This was changed into the, that and it. So i am confused when to change this into the, that and it.