He write the last chapter of his new book by the end of the year. В каком времени должен стоять глагол write?
He had written the last chapter of his new book by the end of the year.( к концу года он дописал)
He will have written the last chapter of his new book by the end of the year.( к концу года он допишет )
Written P.s это уже ответ)