The day before yesterday, the day after tomorrow etc.
Incorrect : He came here before yesterday.
Correct : He came here the day before yesterday.
Incorrect : I shall visit you after tomorrow.
Correct: I shall visit you the day after tomorrow.
Incorrect : She will come here after next week.
Correct : She will come here the week after next.
Note: The phrases "before yesterday', 'after tomorrow’ or "after next week’ are not correct.
