I love the tennis game,especially the  grand slam also called majors, 
I like tennis too. What exactly is a grand slam in tennis though?
They are the major tennis game with the highest reward but highly competitive. Australian Open in mid January, the French Open in May and June 
Oh so those are the most important games for players to win. Which tennis players have won the most grand slams?
On the men's single players .we have the Big four ,they are Roger Federer, Rafael Nadal, Novak Djokovic, and Andy Murray.
I know Roger Federer he has been playing forever right?
Roger Federer
Roger Federer (; born 8 August 1981) is a Swiss professional tennis player who is currently ranked world No. 3 in men's singles tennis by the Association of Tennis Professionals (ATP). He has won 20 Grand Slam singles titles—the most in history for a male player—and has held the world No. 1 spot in the ATP rankings for a record total of 310 weeks, including a record 237 consecutive weeks. After turning professional in 1998, he was continuously ranked in the top ten
Grand Slam (tennis)
The Grand Slam tournaments, also called majors, are the four most important annual tennis events. They offer the most ranking points, prize money, public and media attention, the greatest strength and size of field, and greater number of "best of" sets for men, which is 5. The Grand Slam itinerary consists of the Australian Open in mid January, the French Open around late May through early June, Wimbledon in June-July, and the US Open in August-September