20 17 why are so many premier league games postponed to 28 rounds?

Because many teams have FA Cup matches this week, the corresponding matches of Premier League teams have been postponed.

2017-03-1120:15 Middlesbrough VS Manchester city?

2017-03-1201:30 arsenal vs Lincoln city?

20 17-03- 12 22:00 Tottenham vs Millwall?

20 17-03- 14 03:45 Chelsea vs Manchester United