Simplify the following text for a Grade 17 native English-speaking person.
Original: The 2011 WTA Tour calendar comprises the Grand Slam tournaments ( organised by the International Tennis Federation ( ITF ) ) , the WTA Premier tournaments ( Premier Mandatory , Premier 5 and regular Premier ) , the WTA International tournaments , the Fed Cup ( organised by the ITF ) , and the year-end championships ( the Commonwealth Bank Tournament of Champions and the WTA Tour Championships ) .
Simplified: The 2011 WTA Tour includes the Grand Slam tournaments ( sanctioned by the International Tennis Federation ( ITF ) ) , the WTA Premier tournaments , the WTA International tournaments , the Fed Cup ( organized by the ITF ) , the Commonwealth Bank Tournament of Champions , and the WTA Championships .