today that day
tonight that night
tomorrow the next (following) day(month, year)
yesterday the day before
yesterday afternoon the afternoon before
last year (month) the year (month) before
He said, "I've just got a letter from my sister."
He said he had just got a letter from his sister.
"He was here a few weeks ago, and he came again yesterday." she said.
She said that he had been there a few weeks before, and that he had come again the day before.